Coatings for Increasing Near-Infrared Detection Distances

ABSTRACT

A method for increasing a detection distance of a surface of an object illuminated by near-IR electromagnetic radiation, including: (a) directing near-IR electromagnetic radiation from a near-IR electromagnetic radiation source towards an object at least partially coated with a near-IR reflective coating that increases a near-IR electromagnetic radiation detection distance by at least 15% as measured at a wavelength in a near-IR range as compared to the same object coated with a color matched coating which absorbs more of the same near-IR radiation, where the color matched coating has a ΔE color matched value of 1.5 or less when compared to the near-IR reflective coating; and (b) detecting reflected near-IR electromagnetic radiation reflected from the near-IR reflective coating. A system for detecting proximity of vehicles is also disclosed.

FIELD OF THE INVENTION

The present invention also relates to methods and systems for increasednear-IR detection distance of an object coated with a near-IR reflectivecoating.

BACKGROUND OF THE INVENTION

Recent advances have been made in technologies related to self-driving(“autonomous”) vehicles and other objects in a vehicle's surroundingsincluding markings that are detectable by a sensor mounted on theautonomous vehicle. Autonomous vehicles use a combination of detectingsystems, such as sensors, cameras, radar, ultrasonic, and lasers todetect and locate obstacles such that the autonomous vehicle can safelynavigate around such objects. Some detecting systems are limited intheir ability to detect objects at long distances or in non-idealenvironments, such as in low-light conditions, in inclement weather,such as fog, rain, and snow, or in other conditions with lightscattering particulates in the air (e.g., smog and dust). Suchlimitations may prohibit the autonomous from safely navigatingobstacles. New detection systems that can increase the detectiondistance and produce detectable signals in non-ideal environments aredesirable.

SUMMARY OF THE INVENTION

The present invention is directed to a method for increasing a detectiondistance of a surface of an object illuminated by near-IRelectromagnetic radiation, including: (a) directing near-IRelectromagnetic radiation from a near-IR electromagnetic radiationsource towards an object at least partially coated with a near-IRreflective coating that increases a near-IR electromagnetic radiationdetection distance by at least 15% as measured at a wavelength in anear-IR range as compared to the same object coated with a color matchedcoating which absorbs more of the same near-IR radiation, where thecolor matched coating has a ΔE color matched value of 1.5 or less whencompared to the near-IR reflective coating, as measured using anintegrating sphere with D65 Illumination, 10° observer with specularcomponent included; and (b) detecting reflected near-IR electromagneticradiation reflected from the near-IR reflective coating.

The present invention is also directed to a system for detectingproximity of vehicles, including: a first vehicle at least partiallycoated with a near-IR reflective coating that increases a near-IRelectromagnetic radiation detection distance by at least 15% as measuredat a wavelength in a near-IR range between the first vehicle and asecond vehicle as compared to the first vehicle coated with a colormatched coating which absorbs more of the near-IR radiation. The colormatched coating has a ΔE color matched value of 1.5 or less whencompared to the near-IR reflective coating, as measured using anintegrating sphere with D65 Illumination, 10° observer with specularcomponent included.

The present invention is also directed to a system for detecting theproximity of a first vehicle to a second vehicle, including: (a) a firstvehicle at least partially coated with a near-IR reflective coating thatincreases a near-IR electromagnetic radiation detection distance by atleast 15% as measured at a wavelength in a near-IR range as compared toa vehicle coated with a similar color matched coating which absorbs moreof the near-IR radiation, where the similar color matched coating has aΔE color matched value of 1.5 or less when compared to the near-IRreflective coating, as measured using an integrating sphere with D65Illumination, 10° observer with specular component included; and (b) asecond vehicle including: (i) a near-IR electromagnetic radiation sourcethat directs near-IR electromagnetic radiation towards the firstvehicle; (ii) a near-IR detector that detects near-IR electromagneticradiation reflected from the first vehicle; and (iii) a computing devicethat determines the detection distance between the first vehicle andsecond vehicle based in part on the detected near-IR electromagneticradiation reflected from the first vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is graphic representation of a front view of a near-IR reflectivecoated test panel secured to a mount; and

FIG. 2 is a schematic drawing illustrating the orientation positions ofa near-IR reflective coated test panel in relation to a LIDAR device.

DETAILED DESCRIPTION OF THE INVENTION

For purposes of the following detailed description, it is to beunderstood that the invention may assume various alternative variationsand step sequences, except where expressly specified to the contrary.Moreover, other than in any operating examples, or where otherwiseindicated, all numbers expressing, for example, quantities ofingredients used in the specification and claims are to be understood asbeing modified in all instances by the term “about”. Accordingly, unlessindicated to the contrary, the numerical parameters set forth in thefollowing specification and attached claims are approximations that mayvary depending upon the desired properties to be obtained by the presentinvention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard variation found in theirrespective testing measurements.

Also, it should be understood that any numerical range recited herein isintended to include all sub-ranges subsumed therein. For example, arange of “1 to 10” is intended to include all sub-ranges between (andincluding) the recited minimum value of 1 and the recited maximum valueof 10, that is, having a minimum value equal to or greater than 1 and amaximum value of equal to or less than 10.

In this application, the use of the singular includes the plural and theplural encompasses the singular, unless specifically stated otherwise.In addition, in this application, the use of “or” means “and/or” unlessspecifically stated otherwise, even though “and/or” may be explicitlyused in certain instances. Further, in this application, the use of “a”or “an” means “at least one” unless specifically stated otherwise. Forexample, “an” object, “a” pigment, and the like refer to one or more ofthese items. Also, as used herein, the term “polymer” may refer toprepolymers, oligomers, and both homopolymers and copolymers. The term“resin” is used interchangeably with “polymer.”

As used herein, the transitional term “comprising” (and other comparableterms, e.g., “containing” and “including”) is “open-ended” and is usedin reference to compositions, methods, and respective component(s)thereof that are essential to the invention, yet open to the inclusionof unspecified matter.

The present invention is directed to methods for increasing a detectiondistance of a surface of an object illuminated by near-infrared(near-IR) electromagnetic radiation. Such methods may include thefollowing steps: (a) directing near-IR electromagnetic radiation from anear-IR electromagnetic radiation source towards an object at leastpartially coated with a near-IR reflective coating that increases anear-IR electromagnetic radiation detection distance by at least 15% asmeasured at a wavelength in a near-IR range as compared to the sameobject coated with a color matched coating which absorbs more of thesame near-IR radiation, wherein the color matched coating has a ΔE colormatched value of 1.5 or less when compared to the near-IR reflectivecoating, as measured using an integrating sphere with D65 Illumination,10° observer with specular component included; and (b) detectingreflected near-IR electromagnetic radiation from the near-IR reflectivecoating.

As used herein, the term “object” refers to a vehicle, road, roadtraffic safety product, signage, building, structure and any obstaclethat may be located in a path of a moving vehicle. Road traffic safetyproducts may include barriers, barricades, speed bumps, traffic cones,and the like. Vehicles may include any type of moving vehicle, such asautomobiles, bicycles, trucks, buses, airplanes, boats, and the like.The vehicle may be autonomously operated. The object may be clothing,such as clothing worn by an individual in the path of a vehicle. It isto be understood that objects may include any type of obstacles that maybe located in the path of any of the types of vehicles.

As used herein, the term “near-IR” or “infrared radiation” or “NIR”refers to electromagnetic radiation in the near-IR range of theelectromagnetic spectrum. Such near-IR electromagnetic radiation mayhave a wavelength from 700 nm to 2500 nm, such as 900-1600 nm, such as905 nm, or such as 1550 nm.

The near-IR electromagnetic radiation source that may be used in thepresent invention includes, without limitation, light emitting diodes(LEDs), laser diodes or any light source that is capable of emittingelectromagnetic radiation having a wavelength from 700 nm to 2500 nm (inthe near-IR range). The near-IR electromagnetic radiation source may beused in an imaging LIDAR (Light Imaging, Detection and Ranging) system.The imaging LIDAR system may utilize lasers to generate electromagneticradiation with a wavelength from 700-2500 nm, such as from 900-1600 nm.The LIDAR system may utilize lasers to generate electromagneticradiation with a wavelength of 905 nm, 1550 nm, or any other suitablewavelength in the near-IR range.

A near-IR detector may be a semiconductor detector that is capable ofsensing near-IR radiation. Such near-IR detectors may include aphotodiode or an image sensor. The near-IR detector may be coupled inthe same housing unit with the near-IR electromagnetic radiation source,such as a LIDAR system that houses both the near-IR source and thedetector.

Alternatively, the near-IR detector may be in a separate housing fromthe near-IR electromagnetic source.

Typically, the near-IR detector and the near-IR source are coupled tothe same vehicle to detect obstacles in the pathway of the vehicle,including an autonomous vehicle. The LIDAR device may also include acomputing system for calculating the distance the near-IRelectromagnetic radiation travels to an object that is capable ofreflecting such electromagnetic radiation. The present invention mayinclude one near-IR detector or a plurality of near-IR detectors. Thepresent invention may include a first near-IR detector capable ofdetecting near-IR electromagnetic radiation having a first wavelengthand a second near-IR detector capable of detecting near-IRelectromagnetic radiation having a second wavelength, where the firstand second wavelengths are different wavelengths, as such the firstwavelength has a shorter wavelength than the second wavelength.

According to the present invention the object may be at least partiallycoated with a near-IR reflective coating. The near-IR reflective coatingmay be a single layer or a multilayer coating system, such as a coatingsystem including at least two coating layers, a first coating layer anda second coating layer underneath at least a portion of the firstcoating layer (second coating layer underlies at least a portion of thefirst coating layer). The first coating layer may be substantiallytransparent to near-IR radiation. The second coating layer may reflectnear-IR radiation. In addition, the near-IR reflective coating systemmay include additional coating layers in addition to the first coatinglayer and the second coating layer.

The near-IR reflective coating of the present invention may be depositedonto any of the previously described objects. The present invention mayprovide a near-IR reflective coating being applied to at least 10% of anexterior surface area of an object, such as at least 20%, such as atleast 50%, at least 70%, or at least 90%.

The near-IR reflective coating of the present invention may be appliedto any substrates known in the art. These substrates may be, forexample, metallic or non-metallic. Metallic substrates may include tin,aluminum, steel, such as, tin-plated steel, chromium passivated steel,galvanized steel, or coiled steel, or other coiled metal, and anymetallic alloys thereof. Non-metallic substrates may be polymeric, suchas plastic, including polyester, polyolefin, polyamide, cellulosic,polystyrene, polyacrylic, poly(ethylene naphthalate), polypropylene,polyethylene, nylon, EVOH, polylactic acid, other “green” polymericsubstrates, poly(ethyleneterephthalate) (“PET”), polycarbonate,polycarbonate acrylobutadiene styrene (“PC/ABS”), or polyamide. Othersuitable non-metallic substrates may include wood, veneer, woodcomposite, particle board, medium density fiberboard, cement, stone,glass, ceramic, asphalt, and the like.

The substrate may be a pretreated metal substrate (such as is mentionedabove) and may be coated with an electrodeposited coating. Suitableelectrodepositable coating compositions have been described in U.S. Pat.Nos. 4,933,056, 5,530,043, 5,760,107, and 5,820,987, incorporated hereinby reference. After the electrodeposited coating composition is cured, aprimer-surfacer coating may be applied onto at least a portion of theelectrodeposited coating. The primer-surfacer coating may be applied tothe electrodeposited coating and cured prior to subsequent applicationof another coating.

The primer-surfacer coating may enhance chip resistance of subsequentlyapplied coating layers, and may enhance the appearance of thesubsequently applied coating layers. The second coating layer of thepresent invention may be a previously-described primer-surfacer coatingor a sealer. In some examples, the first coating layer of the coatingsystem may be a color-imparting basecoat that is deposited onto at leasta portion of the primer-surfacer coating or sealer layer (the secondcoating layer).

The near-IR reflective coating of the present invention may furtherinclude a substantially clear coating (e.g., a clearcoat or top-coat).The clearcoat may be positioned over at least a portion of the firstcoating layer. As used herein, the term “substantially clear” refers toa coating that is substantially transparent and not opaque. Theclearcoat may include a colorant; however, in such cases, the colorantis not present in an amount sufficient to render the coating opaque.Clearcoats described in, for example, U.S. Pat. Nos. 5,989,642,6,245,855, 6,387,519, and 7,005,472, incorporated by reference herein,may be used in the coating systems of the present invention. In certainexamples, the clearcoat may include particles, such as silica particles,that are dispersed in the clearcoat (such as at the surface of theclearcoat).

The first coating layer (which may be the color-imparting basecoat asdescribed above) may also be the clearcoat or top-coat described above,such that a single layer serves as a color-imparting basecoat and theclearcoat over the second coating layer (primer layer). Thus, anadditional clearcoat overtop of the first coating layer may not beincluded, and the first coating layer may serve as the top-coat of thenear-IR reflective coating system. This may be the case in automotiverefinish applications in which the coating layer applied over theprimer-surfacer layer (second coating layer) may be a combined colorbasecoat and clearcoat (in a single layer).

The near-IR reflective coating of the present invention (such as thefirst coating layer of the multilayer coating) may exhibit a CIELAB L*value of no more than 35, such as no more than 30, or no more than 28.For purposes of the present invention, CIELAB L* values are measuredusing an integrating sphere with D65 Illumination, 10° observer withspecular component included. The L*, a*, b*, C*, h°, and ΔE CIELABvalues reported herein are determined using an integrating sphere withD65 Illumination, 10° observer with specular component includedaccording to ASTM 308 unless otherwise stated.

The first coating layer of the near-IR reflective coating system of thepresent invention may include: (a) a film-forming resin; and (b) avisibly-absorbing near-IR transparent pigment and/or dye (or othercolorant). As used herein, the term “film-forming resin” may refer to aresin that can form a self-supporting continuous film on at least ahorizontal surface of a substrate upon removal of any diluents orcarriers present with the film-forming resin or upon curing at ambientor elevated temperature.

Film-forming resins that may be used in the first coating layer include,without limitation, those used in automotive OEM coating compositions,automotive refinish coating compositions, industrial coatingcompositions, architectural coating compositions, coil coatingcompositions, packaging coating compositions, protective and marinecoating compositions, and aerospace coating compositions, among others.

The film-forming resin included within the near-IR reflective coatingsdescribed herein may include a thermosetting film-forming resin. As usedherein, the term “thermosetting” refers to resins that “set”irreversibly upon curing or crosslinking, where the polymer chains ofthe polymeric components are joined together by covalent bonds. Thisproperty is usually associated with a cross-linking reaction of thecomposition constituents often induced, for example, by heat orradiation. Curing or crosslinking reactions also may be carried outunder ambient conditions. Once cured or crosslinked, a thermoset resinwill not melt upon the application of heat and is insoluble inconventional solvents. In other examples, the film-forming resinincluded within the coatings described herein may include athermoplastic resin. As used herein, the term “thermoplastic” refers toresins that include polymeric components that are not joined by covalentbonds and thereby can undergo liquid flow upon heating and are solublein conventional solvents.

The near-IR reflective coatings described herein may include any of avariety of thermoplastic and/or thermosetting compositions known in theart. The near-IR reflective coatings may be deposited from water-basedor solvent-based liquid compositions, or, alternatively, a compositionin solid particulate form (e.g., a powder coating).

Thermosetting coating compositions typically include a crosslinkingagent that may be selected from, for example, aminoplasts,polyisocyanates including blocked isocyanates, polyepoxides,beta-hydroxyalkylamides, polyacids, anhydrides, organometallicacid-functional materials, polyamines, polyamides, and mixtures of anyof the foregoing.

Thermosetting or curable coating compositions typically include filmforming resins having functional groups that are reactive with thecrosslinking agent. The film-forming resin in the coatings describedherein may be selected from any of a variety of polymers well-known inthe art. The film-forming resin may be selected from, for example,acrylic polymers, polyester polymers, polyurethane polymers, polyamidepolymers, polyether polymers, polysiloxane polymers, copolymers thereof,and mixtures thereof. Generally these polymers may be any polymers ofthese types made by any method known to those skilled in the art. Thefunctional groups on the film-forming resin may be selected from any ofa variety of reactive functional groups including, for example,carboxylic acid groups, amine groups, epoxide groups, hydroxyl groups,thiol groups, carbamate groups, amide groups, urea groups, isocyanategroups (including blocked isocyanate groups), mercaptan groups, andcombinations thereof.

Appropriate mixtures of film-forming resins may also be used in thepreparation of the near-IR reflective coatings described herein.

The first coating layer in the near-IR reflective coating systems of thepresent invention may include a visibly-absorbing near-IR transparentpigment and/or dye.

As used herein, the term “near-IR transparent pigment and/or dye” mayrefer to a pigment and/or dye that is substantially transparent in thenear-IR range (700 to 2500 nm), such as is described in U.S. PatentApplication Publication No. 2004/0191540 at [0020]-[0026], the citedportion of which is incorporated herein by reference, withoutappreciable scattering or absorption of radiation in such wavelengths.In certain examples, the near-IR transparent pigment and/or dye may havean average transmission of at least 70% in the near-IR wavelengthregion. As used herein, the term “visibly-absorbing” refers to a pigmentand/or dye that substantially absorbs radiation in at least somewavelengths within the visible region of 400 to 700 nm.

Non-limiting examples of suitable visibly-absorbing near-IR transparentpigments may include, for example, copper phthalocyanine pigment,halogenated copper phthalocyanine pigment, anthraquinone pigment,quinacridone pigment, perylene pigment, monoazo pigment, disazo pigment,quinophthalone pigment, indanthrone pigment, dioxazine pigment,isoindoline pigment, diarylide yellow pigment, brominated anthranthronepigment, azo metal complex pigment, and the like. Combinations of thevisibly-absorbing near-IR transparent pigments may be used.

The near-IR transparent pigment may include a near-IR transparent blackpigment, such as those that rely in part upon a perylene type structure,that is illustrated below:

Commercially available examples of such pigments include PALIOGEN® BlackEH 0788, PALIOGEN® Black L0086, and PALIOGEN® Black S0084, commerciallyavailable from BASF Corporation (Ludwigshafen, Germany). Furtherexamples of near-IR transparent black pigments that are suitable for usein certain embodiments of the present invention are described in U.S.Patent Application Publication No. 2009/0098476 at [0030] to [0034], thecited portion of which is incorporated by reference herein, and includesthose having a perylene isoindolene structure, an azomethine structure,and/or an aniline structure.

The near-IR transparent pigment and/or dye may be present in thecomposition from which the first coating layer is deposited in an amountof at least 0.5% by weight, such as at least 1% by weight, or at least5% by weight, based on the total solids weight of the composition. Thenear-IR transparent pigment and/or dye may be present in the compositionfrom which the first coating layer is deposited in an amount of lessthan 20% by weight, such as less than 15% by weight, or less than 10% byweight, based on the total solids weight of the composition. A range ofthe amount of near-IR transparent pigment and/or dye present in suchcompositions may include any combinations of these values, inclusive ofthe recited values, such as 0.5-20%, 1-15%, or 5-10% by weight based onthe total solids weight of the composition.

The first coating layer, as well as the second coating layer, may besubstantially free, or, in some cases, completely free, of carbon black.As used in this application, the term “substantially free”, when usedwith reference to the amount of carbon black in a coating composition,means that carbon black is present in the composition in an amount of nomore than 0.1% by weight, no more than 0.05% by weight, or no more than0.02% by weight, based on the total solids weight of the composition. Asused herein, the term “completely free”, when used with reference to theamount of carbon black in a coating composition, means that carbon blackis not present in the composition at all.

If desired, the first coating layer and/or the second coating layer mayinclude other optional materials well known in the art of formulatingsurface coatings, such as plasticizers, anti-oxidants, hindered aminelight stabilizers, UV light absorbers and stabilizers, surfactants, flowcontrol agents, thixotropic agents such as bentonite clay, pigments,fillers, organic co-solvents, catalysts, including phosphonic acids, andother customary auxiliaries.

The near-IR reflective coating systems of the present invention mayfurther include a second coating layer underlying at least a portion ofthe first coating layer. In some examples, the second coating layer mayinclude: (a) a film-forming resin; (b) a near-IR reflective pigment,such as titanium dioxide pigment or a thin flake metal or metal alloynear-IR reflective pigment; and optionally (c) a visibly-absorbingnear-IR transparent pigment and/or dye (or other colorant). The filmforming resin and visibly-absorbing near-IR transparent pigment and/ordye may include, for example, any of those described earlier withrespect to the first coating layer. In some examples, the film formingresin and/or visibly-absorbing near-IR transparent pigment and/or dyepresent in the second coating layer may be the same as the film-formingresin and/or visibly-absorbing near-IR transparent pigment and/or dyepresent in the first coating layer. In some examples, the film-formingresin and/or visibly-absorbing near-IR transparent pigment and/or dyepresent in the second coating layer may be different from thefilm-forming resin and/or visibly-absorbing near-IR transparent pigmentand/or dye present in the first coating layer.

As used herein, the terms “near-IR reflective pigment” may refer to apigment that, when included in a coating composition, provides a curedcoating with a reflectance of near-IR radiation greater than a curedcoating deposited in the same manner from the same composition butwithout the near-IR reflective pigment.

Suitable examples of thin flakes of metal or metal alloy near-IRreflective pigments may include, for example, aluminum, chromium,cobalt, iron, copper, manganese, nickel, silver, gold, iron, tin, zinc,bronze, brass, including alloys thereof, such as zinc-copper alloys,zinc-tin alloys, and zinc-aluminum alloys, among others. Some specificexamples include nickel antimony titanium, nickel niobium titanium,chrome antimony titanium, chrome niobium, chrome tungsten titanium,chrome iron nickel, chromium iron oxide, chromium oxide, chrometitanate, manganese antimony titanium, manganese ferrite, chromiumgreen-black, cobalt titanates, chromites, or phosphates, cobaltmagnesium, and aluminites, iron oxide, iron cobalt ferrite, irontitanium, zinc ferrite, zinc iron chromite, copper chromite, as well ascombinations thereof.

In the present invention, such pigments may be in the form of thinflakes. For example, “leafing” aluminum flakes are often suitable. Asused herein, the term “thin flake” means that a particle has a ratio ofits width to its thickness (termed aspect ratio) that is at least 2 andoften falls in the range of 10 to 2,000, such as 3 to 400, or, in somecases, 10 to 200, including 10 to 150. As such, a “thin flake” particleis one that has a substantially flat structure. Such flakes may have acoating deposited thereon, such as is the case with silica coated copperflakes.

Such thin flake particles may have a thickness of less than 0.05 micronsto 10 microns, such as 0.5 to 5 microns. In certain examples, such thinflake particles have a maximum width of 10 to 150 microns, such as 10 to30 microns.

The second coating layer may include thin flake particles having roundededges and a smooth and flat surface, as opposed to jagged edges. Flakeshaving angular edges and uneven surfaces are known in the art as“cornflakes”. On the other hand, flakes distinguished by more roundededges and smoother, flatter surfaces are referred to as “silver dollar”flakes. Moreover, in certain examples, the thin flake metal or metalalloy particles having rounded edges may have a maximum width of no morethan 25 microns, such as 10 to 15 microns, when measured according toISO 1524.

Additional suitable thin flake metal or metal alloy near-IR reflectivepigments may include colored metallic pigments, such as those in which acoloring pigment is chemically adsorbed on the surface of a metallicpigment. Such colored metallic pigments are described in U.S. Pat. No.5,037,745 at col. 2, line 55 to col. 7, line 54, the cited portion ofwhich is incorporated herein by reference. Some such colored metallicpigments are also commercially available and include those availablefrom U.S. Aluminum, Inc. (Flemington, N.J.) under the tradenameFIREFLAKE®. Near-IR transparent pigments, such as the perylene-basedpigments described below, may be chemically adsorbed on the surface ofthe metallic pigment, to provide a dark, sometimes black, colorednear-IR reflective metallic pigment.

The thin flake metal or metal alloy near-IR reflective pigments may bepresent in the compositions from which the second coating layer isdeposited in an amount of at least 1% by weight, such as at least 2%, atleast 3%, at least 5%, at least 6%, or at least 10% by weight, based onthe total solids weight of the composition. In some cases, the near-IRreflective pigment can be present in the foregoing coating compositionsin an amount of no more than 50% by weight, such as no more than 25%, orno more than 15% by weight, based on the total solids weight of thecomposition. A range of the amount of thin flake metal or metal alloynear-IR reflective pigments present in such compositions may include anycombinations of these values, inclusive of the recited values, such as1-25%, 5-25%, or 10-15% by weight based on the total solids weight ofthe composition.

The second coating layer may include near-IR reflective pigments inaddition to or in lieu of the thin flake metal or metal alloy near-IRreflective pigments described earlier. Such additional near-IRreflective pigment may be colored or essentially colorless, translucentor opaque. As used herein, the term “essentially colorless” means thatthe pigment does not have a color, e.g., the absorption curve for thepigment is devoid of absorption peaks in the 400-700 nm range and doesnot present a tint or hue in reflected or transmitted light when viewedunder sunlight. A colored near-IR reflective pigment may be a near-IRreflective pigment that is not essentially colorless. Stateddifferently, a “colored” near-IR reflective pigment is one that may bevisibly-absorbing, as defined below. A “translucent” pigment means thatvisible light is able to pass through the pigment diffusely. An “opaque”pigment is one that scatters significant amounts of light. One exampleof a near-IR reflective pigment that can be translucent and essentiallycolorless (if used in small enough amounts in a coating) is SOLARFLAIR®9870 pigment commercially available from Merck KGaA (Darmstadt,Germany). This commercially available pigment may also be an example ofan interference pigment (described below) that has a mica substrate thatis coated with titanium dioxide.

Examples of suitable colored and/or opaque near-IR reflective pigmentsinclude, for example, any of a variety of metals and metal alloys,inorganic oxides, and interference pigments. Exemplary colors include,for example: white, as is the case with titanium dioxide; brown, as isthe case with iron titanium brown spinel; green, as is the case withchromium oxide green; red, as is the case with iron oxide red; yellow,as is the case with chrome titanate yellow and nickel titanate yellow;and blue and violet, as is the case with certain TiO₂ coated micaflakes.

Suitable inorganic oxide containing near-IR reflective pigments include,for example, iron oxide, titanium oxide (TiO₂) pigment, composite oxidesystem pigments, titanium oxide-coated mica pigment, iron oxide-coatedmica pigment, and zinc oxide pigment, among many others.

In one non-limiting example, the second coating layer may include: (a) afilm forming resin; (b) a plurality of near-IR transparent pigmentsand/or dyes dispersed in the film forming resin; and (c) a near-IRreflective pigment dispersed in the film forming resin. In this example,the near-IR transparent pigments and/or dyes may include any of thepreviously-disclosed visibly-absorbing near-IR transparent pigmentsand/or dyes. The second coating layer may include a plurality of near-IRtransparent pigments and/or dyes. The plurality of near-IR transparentpigments and/or dyes may include a first perylene pigment and a secondperylene pigment different from the first perylene pigment. The near-IRreflective pigment may be different from the first perylene pigment andthe second perylene pigment. The second coating layer in this examplemay be substantially free of carbon black and may exhibit an off-whiteor grey color. In this example, substantially free means less than orequal to 0.02% by weight, based on the total solids weight of thecomposition.

In this example, the perylene pigment may be any of thepreviously-described perylene pigments. The coating composition mayinclude a perylene pigment according to formula (a) or (b):

Such pigments are commercially available as PALIOGEN® Black EH 0788 andPALIOGEN® Black EH 0788 from BASF Corporation.

The coating composition may include a perylene pigment according toformula (c):

Such perylene pigment is also known as “CI Pigment Black 32” and iscommercially available as PALIOGEN® Black L 0086 from BASF Corporation.

With continued reference to this example, the first perylene pigment maybe a green-shade perylene pigment, and the second perylene pigment maybe a purple-shade perylene pigment.

The green-shade perylene pigment, when utilized alone at a high enoughconcentration and applied at a suitable dry film thickness, may appearblack to the human eye. However, when the green-shade perylene pigmentis utilized in combination with titanium dioxide in a coatingcomposition (e.g., the same layer of a multilayer coating composition),the coating composition appears to be a green-shade to the human eye.Green-shade means exhibiting CIELAB values using an integrating spherewith D65 Illumination, 10° observer with specular component included of:L* of 40-95 and h° of 275-325.

The purple-shade perylene pigment, when utilized alone at a high enoughconcentration and applied at a suitable dry film thickness, may appearblack to the human eye. However, when the purple-shade perylene pigmentis utilized in combination with titanium dioxide in a coatingcomposition (e.g., the same layer of a multilayer coating composition),the coating composition appears to be a purple-shade to the human eye.Purple-shade means exhibiting CIELAB values using an integrating spherewith D65 Illumination, 10° observer with specular component included of:L* of 40-95 and h° of 170-200.

In this example, the second coating layer may exhibit the followingCIELAB values using an integrating sphere with D65 Illumination, 10°observer with specular component included: a L* value ranging from40-95; an a* value ranging from −2 to 2; and a b* value ranging from −6to 6, which may be considered an off-white or gray color.

With continued reference to this example, the near-IR reflective pigmentmay be titanium dioxide in powder form, which may be dispersed in thefilm-forming resin. The second coating layer may fully hide a surface ofthe object (or the coating layer over which it is applied) at a dry filmthickness of less than or equal to 2.5 mils (63.5 microns), such as lessthan or equal to 2.0 mils (50.8 microns), or less than or equal to 1.5mils (38.1 microns), according to ASTM D6762 using Lenata black andwhite hiding strips. The second coating layer in this example may have atotal solar reflectance of at least 45% as measured in accordance withASTM E903-12, such as at least 50%, at least 60%, at least 65%, at least70%, at least 75%, or at least 80%.

In another non-limiting example, the second coating layer may include: afilm-forming resin; a plurality of colorants dispersed in thefilm-forming resin, the plurality of colorants comprising a near-IRtransparent pigment or dye, wherein the near-IR transparent pigment ordye comprises a first near-IR transparent pigment or dye and a secondnear-IR transparent pigment or dye different from the first near-IRtransparent pigment or dye; and a near-IR reflective pigment dispersedin the film-forming resin, the near-IR reflective pigment different fromthe first near-IR transparent pigment or dye and the second near-IRtransparent pigment or dye, wherein the second coating layer exhibits anoff-white or grey color, and wherein the second coating layer issubstantially free of carbon black.

In this example, the film-forming resin may be any of the previouslydescribed resins.

In this example, the colorant may include pigments, dyes, tints, and/orsome combination thereof, such as those used in the paint industryand/or listed in the Dry Color Manufacturers associate (DCMA), as wellas any special effect compositions. A colorant, as used in thisapplication, may include, for example, a finely divided solid powderthat is insoluble but wettable under the conditions of use. A colorantmay be organic or inorganic and may be agglomerated or non-agglomerated.Colorants may be incorporated into a coating layer (such as the secondcoating layer) by grinding or simple mixing. Colorants may beincorporated by grinding into a coating layer (such as the secondcoating layer) by use of a grind vehicle, such as an acrylic grindvehicle, the use of which will be familiar to one skilled in the art.The colorant may be added to a coating layer (such as the second coatinglayer) in any suitable form, such as discrete particles, dispersions,solutions, and/or flakes. The colorant may be present in a coating layer(such as the second coating layer) in any amount sufficient to impartthe desired property, visual, and/or color effect.

In this example, the first near-IR transparent pigment or dye and thesecond near-IR transparent pigment or dye of the colorant may be any ofthe near-IR transparent pigments or dyes previously disclosed herein.The near IR-reflective pigment may be any of the near-IR reflectivepigments previously disclosed herein.

As used in this application, the term “interference pigment” refers to apigment having a multi-layer structure having alternating layers ofmaterial of different refractive index. Suitable light-interferencepigments include, for example, pigments comprising a substrate of, forexample, mica, SiO₂, Al₂O₃, TiO₂, or glass that is coated with one ormore layers of, e.g., titanium dioxide, iron oxide, titanium iron oxideor chrome oxide or combinations thereof, or pigments comprisingcombinations of metal and metal oxide, such as aluminum coated withlayers of iron oxide layers and/or silicon dioxide.

The near-IR reflective coating system of the present invention may alsoinclude the incorporation of at least one near-IR fluorescent pigmentand/or dye (the first and/or the second layer include at least onenear-IR fluorescent pigment and/or dye). As used herein, the term“near-IR fluorescent pigment” may refer to a pigment that can absorbelectromagnetic radiation in the visible region (400 to 700 nm) andfluoresce in the near-IR region (700 to 2500 nm). Examples of suitablenear-IR fluorescent pigments include metallic pigments, metal oxides,mixed metal oxides, metal sulfides, metal selenides, metal tellurides,metal silicates, inorganic oxides, inorganic silicates, alkaline earthmetal silicates. As used herein, the term “alkaline” refers to theelements of group II of the periodic table Be, Mg, Ca, Sr, Ba, and Ra(beryllium, magnesium, calcium, strontium, barium, radium). Non-limitingexamples of suitable near-IR fluorescent pigments include metalcompounds, which may be doped with one or more metals, metal oxides,alkali and/or rare earth elements. As used herein, the term “alkali”refers to the elements of group I of the periodic table Li, Na, K, Rb,Cs, and Fr (lithium, sodium, potassium, rubidium, cesium, francium). Asused herein, the term “rare earth element” refers to the lanthanideseries of elements La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm,and Yb (lanthanum, cerium, praseodymium, neodymium, promethium,samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium,thulium, and ytterbium).

More particularly, examples of near-IR fluorescent pigments may includeEgyptian blue (CaCuSi₄O₁₀), Han blue (BaCuSi₄O₁₀), Han purple(BaCuSi₂O₆), SrCuSi₄O₁₀, Ruby (Al₂O₃:Cr). In particular, blue alkaliearth copper silicates, such as Egyptian blue (CaCuSi₄O₁₀) fluoresce inthe 800 to 1200 nm region. Cadmium pigments, CdSe and CdTe compounds,“zirconia” red (red cadmium pigments coated with a zirconium silicateglass), indigo, blue verditer (2CuCO₃.Cu(OH)₂), copper blue, azurite(Cu₃(CO₃)₂(OH)₂), Plos s blue ((CuCa)(CH₃COO)₂.2H₂O), and smalt(CoO.K.Si) may possess fluorescence.

Other examples of near-IR fluorescent pigments may include ZnO, ZnS,ZnSe, and ZnTe, which have energy gaps that may be too large forband-to-band emission of near-IR energy, but doping with Sn, Mn, and Temay lead to suitable impurity luminescence. Other examples of near-IRfluorescent pigments may include compounds used in lighting and forfluorescent displays; certain direct bandgap semiconductors, such as(Al,Ga)As, InP, and the like; and materials used for solid state lasers,such as Nd doped yttrium aluminum garnet, and titanium doped sapphire.In addition, examples of near-IR fluorescent pigments may includephosphors that emit in the deep red or near-IR (e.g., LiAlO₂:Fe,CaS:Yb).

The near-IR reflective coating system of the present invention may alsoinclude the incorporation of at least one near-IR fluorescent organicpigment and/or dye. As used herein, the term “near-IR fluorescentorganic pigment and/or dye” refers to an organic pigment and/or dyewhich can absorb electromagnetic radiation in the visible region (400 to700 nm) and fluoresce in the near-IR region (700 to 2500 nm). Examplesof suitable near-IR fluorescent organic pigments and/or dyes include,spiro[indeno[1,2-b]chromene-10,1′-isobenzofuran]-3′-ones,7-(dialkylamino)-3′H,11H-spiro[indeno[1,2-b]chromene-10,1′-isobenzofuran]-3′-ones,changsha (CS1-6) near-IR fluorophores, thienopyrazines, rhodamines, suchas aminobenzofuran-fused rhodamine dyes (AFR dyes) containing aminogroups, sulforhodamine dyes, perylenediimide or hexarylenediimides,donor-acceptor charge transfer compounds such as substituted thiophenes,diphenylbenzobisthiadiazoles, and selenium or tellurium substitutedderivatives, cyclic polyenes, cyclic polyene-ynes, perylenes,perylenebis(dicarboximide)s such as perylene bis(phenethylimide, orperylene bis(2,5-di-tert-butylphenylimide), perylene diimides containingnitrogen donor groups, polymethines, borondipyrromethenes,pyrrolopyrrole cyanines, squaraine dyes, tetrathiafulvalene, thiadiazolefused chromophores, phthalocyanine and porphyrin derivatives,metalloporphyrins, BODIPY (borondipyrromethane) dyes, tricarbocyanines,rubrenes, carbon nanotubes, and graphene and graphene oxide.

The at least one near-IR fluorescent organic pigment and/or dye may beencapsulated as nanoparticles in polymers such as amphiphilic blockcopolymer. For example, an amphiphilic block copolymer encapsulatingnear-IR fluorescent organic pigment and/or dye nanoparticles may bepoly(caprolactone)-b-poly-(ethylene glycol) (PCL-b-PEG). Furthermore,the at least one near-IR fluorescent organic pigment and/or dye may becovalently bonded to the polymer matrix of the encapsulating polymer. Inaddition, the near-IR fluorescent organic pigment and/or dye may beanchored to a polymeric or inorganic particle.

The weight ratio of near-IR reflective pigment to near-IR fluorescentpigment present in the composition from which the second coating layermay be deposited may be at least 1.5:1, such as at least 5:1, at least10:1, or at least 20:1. In other examples, the weight ratio of near-IRreflective pigment to near-IR fluorescent pigment present in thecomposition can be at least 1:1.5, such as at least 1:5, or at least1:10.

According to the present invention, the near-IR fluorescent pigments mayfluoresce or emit electromagnetic radiation at a different wavelengththan the reflected electromagnetic radiation from the near-IR reflectivepigments. For example, a multi-layer coating system that incorporatesboth the near-IR fluorescent pigments and the near-IR reflectivepigments may be capable of absorbing electromagnetic radiation in thevisible region and fluoresce at a longer wavelength than the reflectivenear-IR pigments. For example, the near-IR fluorescent pigments mayabsorb electromagnetic radiation from 400 nm-700 nm and fluoresce at awavelength greater than 1000 nm while the near-IR reflective pigmentscan reflect electromagnetic radiation having a wavelength of 905 nm. Inthis example, it may be possible to employ a near-IR sensor or aplurality of sensors to detect the different wavelengths. With thisexample in mind, one skilled in the art may develop a multi-layercoating system that has a unique near-IR signature (e.g., multiplenear-IR signals).

In certain examples of the present invention, the second coating layermay be, like the first coating layer, substantially free, or, in somecases, completely free, of carbon black. If desired, the second coatinglayer may include other optional materials well known in the art offormulated surface coatings, such as any of those described earlier withrespect to the first coating layer. In certain examples, the near-IRreflective coating may be substantially free of carbon black, includingall layers thereof (e.g., the first coating layer, the second coatinglayer, and any other coating layer).

One advantage of the coating systems of the present invention is thatproper use of visually opaque near-IR reflective pigments in the secondcoating layer, such as the thin flake metal, metal alloy or metal oxidenear-IR reflective pigments described earlier, may enable the productionof a coating layer that has the requisite hiding at relatively low dryfilm thicknesses, such as no more than 2 mils (50.8 microns), such as nomore than 1 mil (25.4 microns), or no more than 0.5 mil (12.7 microns).

The coating compositions from which each of the coatings described aboveare deposited may be applied to a substrate by any of a variety ofmethods including dipping or immersion, spraying, intermittent spraying,dipping followed by spraying, spraying followed by dipping, brushing, orroll-coating, among other methods. In certain examples, the coatingcompositions may be applied by spraying and, accordingly, suchcompositions may have a viscosity that is suitable for application byspraying at ambient conditions.

After application of a coating composition to the substrate, it may beallowed to coalesce to form a substantially continuous film on thesubstrate. Typically, the dry film thickness will be 0.01 mil to 20 mils(0.25 microns to 508 microns), such as 0.01 mil to 5 mils (0.25 micronto 127 microns), or, in some cases, 0.1 mil to 2 mils (2.54 microns to50.8 microns) in thickness. A method of forming a coating film accordingto the present invention, therefore, may include applying a coatingcomposition to the surface of a substrate or article to be coated,coalescing the coating composition to form a substantially continuousfilm and then curing the thus-obtained coating. In certain examples, thecuring of these coatings may include a flash at ambient or elevatedtemperatures followed by a thermal bake. In some cases, curing may occurat ambient temperature of 20° C. to 175° C., for example.

When comparing an object coated with the near-IR reflective coating ofthe present invention with an object coated with a color matched coatingwhich absorbs more of the same near-IR radiation, the near-IR radiationdetection distance can be increased by at least 15%. The color matchedcoating typically has a ΔE color matched value of 1.5 or less whencompared to the near-IR reflective coating, as measured using anintegrating sphere with D65 Illumination, 10° observer with specularcomponent included. In some cases, the ΔE color matched value may be 1.0or less or 0.8 or less. The radiation detection distance means themaximum distance between the radiation source and the object for whichdetection of the object is accomplished with the radiation detectionsystem, such as a LIDAR system. According to the present invention thenear-IR reflective coating is capable of increasing the near-IRelectromagnetic radiation detection distance by at least 15%, such as atleast 25%, or at least 35%.

The ΔE color match value between a near-IR coating and a conventionalcoating with the near-IR reflective pigments can be determined using L*,a*, and b* values, which define coordinates in color space. ΔE is thedifference between two colors based on the difference between collectedvalues of L*, a*, and b* according to Equation 1 (below).

ΔE=√{square root over ((ΔL*)²+(Δa*)²+(Δb*)²)}  Equation 1

Depending on the color and the reflective pigments incorporated in thecoating, the near-IR reflective coating of the present invention mayhave near-IR reflectance properties such that the coating has areflectance of at least 20% as measured at an electromagnetic wavelengthin the near-IR range (e.g., 905 nm, 1550 nm, or any other wavelength inthe near-IR range, such as 900 nm-1600 nm), such as at least 70%. Forexample, a near-IR reflective coating having a visible black color mayhave a reflectance of at least 70% when measured at an electromagneticradiation in the near-IR range (e.g., 905 nm, 1550 nm, or any other inthe near-IR range, such as 900 nm-1600 nm). In another example, thenear-IR reflective coating having a visible blue color may have areflectance of at least 20% when measured at an electromagneticradiation in the near-IR range (e.g., 905 nm, 1550 nm, or any otherwavelength in the near-IR range, such as 900 nm-1600 nm).

The present invention may include a system for detecting proximity ofvehicles including a first vehicle at least partially coated with anear-IR reflective coating that increases a near-IR electromagneticradiation detection distance by at least 15% as measured at a wavelengthin a near-IR range between the first vehicle and a second vehicle ascompared to the first vehicle coated with a color matched coating whichabsorbs more of the near-IR radiation. The color matched coating has aΔE color matched value of 1.5 or less when compared to the near-IRreflective coating. The second vehicle may be an autonomously operatedvehicle.

The present invention may include a system for detecting the proximityof a first vehicle to a second vehicle, including: (a) a first vehicleat least partially coated with a near-IR reflective coating thatincreases a near-IR electromagnetic radiation detection distance by atleast 15% as measured at a wavelength in a near-IR range as compared toa vehicle coated with a similar color matched coating which absorbs moreof the near-IR radiation, wherein the similar color matched coating hasa ΔE color matched value of 1.5 or less when compared to the near-IRreflective coating; and (b) a second vehicle including: (i) a near-IRelectromagnetic radiation source that directs near-IR electromagneticradiation towards the first vehicle; (ii) a near-IR detector thatdetects near-IR electromagnetic radiation reflected from the firstvehicle; and (iii) a computing device that determines the detectiondistance between the first vehicle and second vehicle based in part onthe detected near-IR electromagnetic radiation reflected from the firstvehicle. The second vehicle may be an autonomously operated vehicle.

Referring to FIGS. 1 and 2, an exemplary test system 10 for determiningdetection distance is shown. This test system 10 includes a mount 12 towhich a panel 14 is pivotably mounted. The panel 14 is coated with thenear-IR reflective coating previously described herein. The test system10 may also include a near-IR electromagnetic radiation source 16 thatdirects near-IR electromagnetic radiation 18 towards the coated panel14. The coated panel 14 may be positioned at an angle normal to theradiation source 16 (90°) (see FIG. 1) or positioned at a 30° anglerelative to the normal angle (see FIG. 2).

The test system 10 may also include a near-IR detector 17 that detectsnear-IR electromagnetic radiation that reflects off of the coated panel14. As shown in FIG. 2, the radiation source 16 and the near-IR detector17 may be integrated into the same device/housing unit or may beseparate devices (not shown). As shown in FIG. 2, the radiation source16 directs near-IR radiation 18 towards the coated panel 14. Thedistance between the radiation source 16 and the coated panel 14 may bea distance 20, which may be calculated by a computing device (not shown)based on part on the near-IR radiation 18 reflected off of the coatedpanel 14.

While the test system 10 shown in FIGS. 1 and 2 merely shows a simplepanel 14 attached to a generic mount 12, it will be appreciated that theconcepts of this test system 10 may translate to thepreviously-described system in which the mount 12 is a vehicle (or otherpreviously described object) and the test panel 14 is the near-IRreflective coating on the surface of the vehicle (or other previouslydescribed object).

EXAMPLES

The following examples are presented to demonstrate the generalprinciples of the invention. The invention should not be considered aslimited to the specific examples presented.

Example 1

A cellulose acetate butyrate resin mixture was prepared using theingredients and amounts listed in Table 1.

TABLE 1 Cellulose Acetate Butyrate Resin Component Amount (kg) Normalbutyl alcohol 16.8 Xylene 3.4 N-butyl acetate (urethane grade) 64.5Cellulose acetate butyrate - CAB 531-1¹ 15.3 Total formula weight 100.0¹Commercially available from Eastman Chemical (Kingsport, TN)

Solvents were combined and stirred at a low speed using a cowles bladeattached to an air motor. While stirring at a low speed (from 1000RPM-1400 RPM), half of the total mass of cellulose acetate butyrateresin was added slowly. The mixture was then stirred at high speed for10 minutes. After 10 minutes, the stir rate was adjusted back to a low(from 1000 RPM-1400 RPM) speed and the remaining cellulose acetatebutyrate resin was added slowly. Once all the cellulose acetate butyratewas added, the mixture was stirred at high speed (approximately 1500RPM) for 30 minutes or until the cellulose acetate butyrate wascompletely dissolved.

Example 2

An acrylic resin was synthesized using the ingredients and amountslisted in Table 2.

TABLE 2 Acrylic Resin Amount Component (kg) Glycidyl ester - CARDURA ®E-10P² 10.6 Methyl ether propylene glycol acetate 11.7 Xylene 27.7Styrene monomer 17.4 Hydroxyethyl methacrylate 12.5 Methyl methacrylate(MeHQ inhibited) 8.3 Glacial acrylic acid (inhibited) 3.5 Tertiarydodecane thiol 1.5 Di-tertiary butyl peroxide 1.7 Aromatic hydrocarbonmixture- 100 type 3.4 N-butyl acetate (urethane grade) 1.9 Total formulaweight 100.0 ²Commercially available from Hexion (Columbus, OH)

A reactor vessel was charged with 100% N₂ for 20 minutes to purge beforesetting to reflux. The N₂ was turned off after 10 minutes, the reactorwas set to reflux, and 10% N₂ was applied. CARDURA® TM E-10P was addedto the reactor along with 94% of the total mass of methyl etherpropylene glycol acetate and 75% of the total mass of xylene. Themixture was heated to a reflux temperature of 290-295° F. (143-146° C.).Once the solution was refluxing, monomer and catalyst feeds were addedto the reactor. A mixture of monomers including styrene monomer,hydroxyethyl methacrylate, methyl methacrylate, glacial acrylic acid,and tertiary dodecane thiol was added at a feed rate of 6.9 kg/min overthe course of 2 hours. A mixture of di-tertiary butyl peroxide and 13%of the total mass of xylene was also added over the course of 2 hours ata feed rate of 9.6 kg/min. After 2 hours, when the monomer and catalystfeed were complete, solvent was added to the mixture. The first solventrinse included 4% of the total mass of xylene. The second solvent rinseincluded 2% of the total mass of xylene. After the solvent rinses, thereactor was kept at reflux temperature for 4 hours. After 4 hours, thereactor was cooled. Once the reactor reached a temperature below 250° F.(121° C.), the contents of the reactor were removed to a thin tank.Solvents, including aromatic hydrocarbon mixture and N-butyl acetate,were added to the reactor and the rinsed contents were added to the thintank. The resin mixture was cooled to 125° F. (52° C.) and the remainingxylene and methyl ether propylene glycol acetate were added to themixture. The amounts added corresponded to 5% of the total mass ofxylene and 6% of the total mass of methyl ether propylene glycolacetate. The fully formulated resin was filtered through a press andCELITE® 545, a filter aid, commercially available from Sigma-Aldrich(St. Louis, Mo.).

Example 3

Silica Dispersions 1 and 2 were synthesized using the ingredients andamounts listed in Tables 3 and 4, respectively.

TABLE 3 Silica Dispersion 1 Amount Component (kg) Acrylic resin (Example2) 82.4 N-butyl acetate (urethane grade) 15.7 Fumed silica - AEROSIL ®200³ 1.9 Total formula weight 100.0 ³Commercially available from EvonikIndustries (Essen, Germany)

Silica Dispersion 1 was prepared by combining 30% of the total mass ofacrylic resin in Example 2 with 39% of the total mass of N-butyl acetateand 100% of the total mass of AEROSIL® 200. The mixture was stirred athigh (approximately 1500 RPM) speed using a cowles blade attached to anair motor for 20 minutes. The mixture was milled using a Premier millcontaining 1.7 mm-2.4 mm Zirconox media which occupied 70% of the millvolume. The mixture was milled until a 7.0 rating was achieved using aHegman gauge. The mixture was then collected from the mill in a washoutstep which added 3% of the total mass of acrylic resin (Example 2) and22% of the total mass of N-butyl acetate. The collected mixture wasstirred at a low (from 1000 RPM-1400 RPM) speed using a cowles bladeattached to an air motor. While stirring at low (from 1000 RPM-1400 RPM)speed, the remaining mass of acrylic resin (Example 2) and N-butylacetate were added slowly. The amounts added correspond to 67% of thetotal mass of acrylic resin (Example 2) and 39% of the total mass ofN-butyl acetate. The fully formulated Silica Dispersion 1 was stirred athigh (approximately 1500 RPM) speed using a cowles blade for 20 minutes.

TABLE 4 Silica Dispersion 2 Amount Component (kg) N-butyl acetate(urethane grade) 71.2 Xylene 2.4 Normal butyl alcohol 11.8 Celluloseacetate butyrate - CAB 531-1⁴ 10.7 Fumed silica - AEROSIL ® 200⁵ 1.9Total formula weight 100.0 ⁴Commercially available from Eastman Chemical(Kingsport, TN) ⁵Commercially available from Evonik Industries (Essen,Germany)

Silica Dispersion 2 was prepared by combining 94% of the total mass ofN-butyl acetate shown in Table 4 with 100% of the total mass of xyleneand 100% of the total mass of normal butyl alcohol. The mixture wasstirred at low (from 1000 RPM-1400 RPM) speed using a cowles bladeattached to an air motor. While stirring at low (from 1000 RPM-1400 RPM)speed, the cellulose acetate butyrate was added slowly. Once all thecellulose acetate butyrate was added, the mixture was stirred at a high(approximately 1500 RPM) speed for 30 minutes or until the celluloseacetate butyrate was complete dissolved. The AEROSIL® 200 was added, themixture was stirred at high speed for 20 minutes. The mixture was milledusing a Premier mill containing 1.7 mm-2.4 mm Zirconox media(commercially available from Jyoti Ceramic Industries PVT. LTD.(Maharashtra, India)) which occupied 70% of the mill volume. The mixturewas milled at approximately 2000 FPM until a 6.0 rating was achievedusing a Hegman gauge. The mixture was then collected from the mill in awashout step with added 6% of the total mass of N-butyl acetate. Thecollected mixture was stirred at high (approximately 1500 RPM) speedusing a cowles blade attached to an air motor for 1 hour.

Example 4

Near-IR transparent black tint pastes were prepared using theingredients and amounts listed in Tables 5.

TABLE 5 Near-IR Transparent Black Tint Pastes Paste TB1 Paste TB2Component (kg) (kg) Cellulose acetate butyrate resin mixture - 39.6 39.6(Example 1) Acrylic resin - (Example 2) 12.2 12.2 Silica Dispersion 1 -(Example 3) 8.5 8.5 Methyl ether propylene glycol 6.3 6.3 N-butylacetate (urethane grade) 7.8 7.8 Aromatic hydrocarbon mixture - 100 type2.5 2.5 Wetting and dispersing additive - 2.3 2.3 DISPERBYK ® −161⁶Black pigment - PALIOGEN ® Black L0086⁷ 13.8 0 Black pigment -PALIOGEN ® Black EH-0788⁸ 0 13.8 Silica Dispersion 2 - (Example 3) 5.65.6 Ethoxy propyl acetate 1.2 1.2 Polyether modified polysiloxane - 0.10.1 BORCHI ® Gol OL 17⁹ Benzotriazole UV absorber - EVERSORB ® 74¹⁰ 0.10.1 Total formula weight 100.0 100.0 ⁶Commercially available from BYKAdditives and Instruments (Wesel, Germany) ⁷Commercially available fromBASF Corporation (Ludwigshafen, Germany) ⁸Commercially available fromBASF Corporation (Ludwigshafen, Germany) ⁹Commercially available fromBorchers (Westlake, OH) ¹⁰Commercially available from Everlight ChemicalIndustrial Corp. (Taiwan)

Tint pastes TB1 and TB2 were each prepared by combining the components,in the order shown in Table 5. DISPERBYK®-161 and pigments PALIOGEN®Black L0086 and PALIOGEN® Black EH-0788 were added to the respectivetint paste mixtures while stirring at low speed (from 1000 RPM-1400 RPM)using a cowles blade attached to an air motor. Following the addition ofpigment, the tint paste mixtures were stirred at high (approximately1500 RPM) speed using a cowles blade for 20 minutes. Both tint pastemixtures were milled using a Premier mill containing 1.2 mm-1.7 mmZirconox media (commercially available from Jyoti Ceramic IndustriesPVT. LTD. (Maharashtra, India)) which occupied 75% of the mill volume.Both tint paste mixtures were milled at a speed from 2300-2600 FPM untila 6.5 rating was achieved using a Hegman gauge. The tint paste mixtureswere then collected from the mill in a washout step with ethoxy propylacetate and Silica Dispersion 2 (Example 3). Additional components,including BORCHI® Gol OL 17, a polyether modified polysiloxane, andEVERSORB® 74, the benzotriazole UV absorber, were added and the fullyformulated tint paste mixtures were stirred at high speed (approximately1500 RPM) using a cowles blade for 20 minutes.

Example 5

Conventional and near-IR reflective coating stacks were prepared usingthe components listed in Tables 6 and 7.

TABLE 6 Coating Stacks Compo- Conventional Near-IR Reflective nentCoating Stack Coating Stack Substrate ACT CRS C700 C59 ACT CRS C700 C59ED6465¹¹ ED6465¹¹ Sealer DELTRON ® DELTRON ® V-SEAL ™ DAS V-SEAL ™ DASG61¹² 3021¹³ White none DELTRON ® DMD topcoat 1684¹³ Colored DMD 16xx(multiple; DMD 16xx (multiple; topcoat colored)¹⁴ colored)¹⁴ DMD 1683(black)¹⁵ TB1 and TB2 from Example 4 (black) Clearcoat DELTRON ® DC4000¹⁵ DELTRON ® DC 4000¹⁵ ¹¹Commercially available from ACT (Hillsdale,MI); Cold rolled steel (CRS) was prepared by ACT using PPG Industries,Inc. (Pittsburgh, PA) products and procedures as follows- alkalinecleaner (ChemKleen 2010LP), Versabond pretreatment (C700) with Chemseal59 rinse (C59) and Electrocoat (ED6465). ¹²Acrylic urethane sealercommercially available from PPG Industries, Inc. (Pittsburgh, PA)¹³Acrylic urethane sealer commercially available from PPG Industries,Inc. (Pittsburgh, PA) ¹⁴Acrylic tint paste commercially available fromPPG Industries, Inc. (Pittsburgh, PA) ¹⁵Acrylic urethane clearcoatcommercially available from PPG Industries, Inc. (Pittsburgh, PA)

TABLE 7 Tint Pastes and Resins Used to Make Colored Topcoats ColoredTopcoat Use Near-IR Component Description Conventional reflective DMD1683¹⁶ Basecoat black R1, DR1, BK1, None BL1, DBL1 DMD 1677¹⁶ Scarletred R1, DR1 R2, DR2 DMD 1611¹⁶ Bright Orange R1, DR1 R2, DR2 DMD 1608¹⁶Organic orange R1, DR1 R2, DR2 DMD 1627¹⁶ Indo blue BL1, DBL1 BL2, DBL2DMD 1621¹⁶ Fine titanium white BL1 BL2 TB1 (Example 4) Near-IRtransparent None R2, DR2, BK2, black BL2, DBL2 TB2 (Example 4) Near-IRtransparent None R2, DR2, BK2, black BL2, DBL2 DBC 500¹⁷ Color blenderresin None BK2 ¹⁶Acrylic tint paste commercially available from PPGIndustries, Inc. (Pittsburgh, PA) ¹⁷Acrylic coating commerciallyavailable from PPG Industries, Inc. (Pittsburgh, PA)

Acrylic urethane sealer coatings were applied directly to substrates inconventional and near-IR reflective coatings stacks. Conventionalsystems used a gray PPG DELTRON® V-SEAL™ DAS G6 sealer and near-IRreflective systems used a white PPG DELTRON® V-SEAL™ DAS 3021 sealer.Sealers were prepared for spray application by mixing DAS 3021 or DAS G6gray, prepared by combining DAS 3025 and DAS 3027 (to achieve DAS G6gray) with DCX 3030 (commercially available from PPG Industries, Inc.(Pittsburgh, Pa.)) and DT 870 reducer (commercially available from PPGIndustries, Inc. (Pittsburgh, Pa.)) in a 3:1:1 v/v ratio. For DAS G6sealer, this ratio was 2:1:1:1 v/v (DAS 3025: DAS 3027: DCX 3030: DT870).

Corresponding masses of each component are recorded in Table 8 below.Each mixture was agitated prior to spray application by stirring.Sealers were sprayed over substrates using a high volume low pressure(HVLP) gravity fed spray gun (SATA jet 4000) with a 12″ fan spray and 27psi at the gun nozzle (1.4 mm opening). DAS G6 and DAS 3021 sealers wereeach applied on their respective substrate as one coat. For the near-IRreflective coating stack, white topcoat (DMD 1684) was appliedimmediately over DAS 3021. Coatings were cured at ambient temperature(20° C.) for 15 min. Topcoats were applied after cure or within 72hours.

TABLE 8 Sealers as Prepared for Spray Application DAS G6 DAS 3021Component Description (g) (g) DAS 3025 Gray sealer 236.8 0.0 DAS 3027Dark gray sealer 121.7 0.0 DAS 3021 White sealer 0.0 359.0 DCX 3030Isocyanate hardener 75.7 75.4 DT 870 Reducer 65.8 65.6 Total formulaweight 500.0 500.0

Example 6

A white colored topcoat was prepared and applied as follows:

A white colored topcoat (PPG DELTRON® DMD 1684) was applied directlyover DAS 3021 sealer used in near-IR reflective coating stacks. Thewhite topcoat was applied immediately after application of DAS 3021sealer. The white topcoat included a bright white tint paste containingtitanium dioxide (DMD 1684) that was diluted with DT 870 reducer in a1:1 v/v ratio. Corresponding masses of each component are shown in Table9. The mixture was agitated prior to spray application by stirring. Twocoats were applied over DAS 3021 using an HVLP gravity fed spray gun(SATA jet 4000) with a 12″ fan spray and 27 psi at the gun nozzle (1.4mm opening) with a 10 min period at ambient temperature between coats.Coatings were cured at ambient temperature (20° C.) for 20 min beforeapplication of any additional coatings.

TABLE 9 White Topcoats as Prepared for Spray Application DMD 1684Component Description (g) DMD 1684 White tint paste 121.47 DT 870Reducer 78.53 Total formula weight 200.0

Example 7

Colored topcoats were prepared and applied as follows:

Colored topcoats for conventional and near-IR reflective coating stackswere formulated with multiple PPG DELTRON® solvent borne tint pastes(DMD 16xx) to achieve shades of red (R), dark red (DR), black (BK), blue(BL), or dark blue (DBL). For near-IR coating stacks, carbon black tintpaste (DMD 1683) was completely removed and substituted with a blend ofnear-IR transparent perylene black tint pastes prepared in Example 4(TB1 and TB2). Mixtures of colored tint pastes used for conventionaltopcoats (R1, DR1, BK1, BL1, and DBL1) and those used for near-IRtopcoats (R2, DR2, BK2, BL2, and DBL2) were diluted with DT 870 reducerin a 1:1 v/v ratio. Corresponding masses of each component are recordedin Table 10. The mixtures were agitated prior to spray application bystirring. An HVLP gravity fed spray gun (SATA jet 4000) with a 12″ fanspray and 27 psi at the gun nozzle (1.4 mm opening) was used to sprayapply the coatings. Conventional topcoats containing carbon black (R1,DR1, BK1, BL1, and DBL1) were applied over DAS G6 sealer. Coatingscontaining near-IR transparent black tint pastes (R2, DR2, BK2, BL2, andDBL2) were applied over DAS 3021/DMD 1684 sealer/white topcoat. Coloredtopcoats were allowed to flash between multiple coats for 5-10 minutesand were considered dry when the coatings were tack free (15-20 minutesat 20° C.).

TABLE 10 Colored Topcoats as Prepared for Spray Application Descrip- R1R2 DR1 DR2 BK1 BK2 BL1 BL2 DBL1 DBL2 Component tion (g) (g) (g) (g) (g)(g) (g) (g) (g) (g) DMD 1683 Basecoat 6.0 0.0 20.8 0.0 105.2 0.0 4.7 0.010.0 0.0 black DMD 1677 Scarlet 80.9 83.9 61.4 70.5 0.0 0.0 0.0 0.0 0.00.0 red DMD 1611 Bright 4.1 4.2 12.8 13.9 0.0 0.0 0.0 0.0 0.0 0.0 orangeDMD 1608 Organic 16.2 16.8 12.3 14.1 0.0 0.0 0.0 0.0 0.0 0.0 orange DMD1627 Indo blue 0.0 0.0 0.0 0.0 0.0 0.0 62.6 67.8 132.5 137.0 DMD 1621Fine 0.0 0.0 0.0 0.0 0.0 0.0 3.5 3.6 0.0 0.0 titanium white TB1 Near-IR0.0 2.4 0.0 7.8 0.0 20.7 0.0 1.6 0.0 3.1 (Example 4) transparent blackTB2 Near-IR 0.0 0.4 0.0 1.4 0.0 3.7 0.0 0.3 0.0 0.6 (Example 4)transparent black DBC 500 Color 0.0 0.0 0.0 0.0 0.0 81.6 0.0 0.0 0.0 0.0blender DT 870 Reducer 92.8 92.2 92.7 92.4 94.8 94.0 129.2 126.7 57.559.4 Total formula weight 200.0 200.0 200.0 200.0 200.0 200.0 200.0200.0 200.0 200.0

Example 8

A clearcoat was prepared and applied as follows:

PPG DELTRON® solvent borne clearcoat (Velocity Premium Clearcoat; DC4000) was prepared by mixing DC 4000 with hardener (DCH 3085) in a 4:1v/v ratio. Corresponding masses of each component are shown in Table 11.The mixtures were agitated prior to spray application by stirring.Clearcoats were applied in two coats over tack-free top coats using anHVLP gravity fed spray gun (SATA jet 4000) with a 12″ fan spray and 27psi at the gun nozzle (1.4 mm opening). Clearcoats were applied usingtwo coats with a 5-7 minute flash at ambient temperature (20° C.)between coats for 5-10 minutes. Clearcoats were cured in a convectionoven at 60° C. for 20 minutes.

TABLE 11 Clearcoat as Prepared for Spray Application DMD 1684 ComponentDescription (g) DC 4000 Velocity premium clearcoat 391.1 DCH 3085 Midtemperature hardener 109.0 Total formula weight 500.1

Example 9

Coatings were measured for opacity as follows:

Coatings described in Examples 6-8 were drawn down over black and whiteopacity charts (BYK Leneta) using stainless steel rods wrapped with wireof varied diameter (from RD Specialties, Inc. (Webster, N.Y.)). Thisdetermined the dry film thickness necessary for each coating toeliminate the transmission of light in the visual spectrum (400 nm-700nm) to the underlying coating or substrate.

To measure opacity, an integrating sphere spectrophotometer (X-riteColor i7) was used to diffusely illuminate the samples and measure totallight reflected (L*). L* represents the lightness of the sample whereL*=0 is black and L*=100 is diffuse white. Opacity was calculated bytaking the ratio of two L* measurements for each coating, one over theblack side of the chart and one over the white side of the chart(Equation 2). A coating was determined to be opaque when a value of 100was achieved. Dry film thicknesses for coatings described in Examples6-8 used to achieve opacity are reported in Table 12.

$\begin{matrix}{{Opacity} = {\left( \frac{{L^{*}{sample}\mspace{14mu} {over}\mspace{14mu} {white}}\;}{L^{*}{sample}\mspace{14mu} {over}\mspace{14mu} {black}} \right) \times 100}} & {{Equation}\mspace{14mu} 2}\end{matrix}$

For near-IR reflective coating stacks, DAS 3021 sealer achieved opacityby using a combination of one coat of DAS 3021 and two coats of whitetopcoat (DMD 1684).

TABLE 12 Dry Film Thickness Values to Achieve Coating Opacity Dry filmthickness Coating(s) Number of coats (μm) DAS G6 1 20 DAS 3021, 1,  37,DMD 1684 2 20 R1 3 20 R2 3 18 DR1 2 13 DR2 2 11 BK1 3 11 BK2 3 18 BL1 214 BL2 2 14 DBL1 3 18 DBL2 3 19

Example 10

Coatings were color matched by the follow methods:

Conventional and near-IR reflective coating stacks were evaluated incolor space to determine a visual color match. Complete coating stacks(C-) were defined by color (R, DR, BK, BL, and DBL). An integratingsphere spectrophotometer (X-rite Color i7) was used to evaluateconventional and near-IR systems where each layer within the system wasapplied to achieve opacity (Example 9). A color match betweenconventional and near-IR reflective systems was determined using L*, a*,and b* values, which define coordinates in color space. Delta E (ΔE) wasused to calculate the difference between two colors based on thedifference between collected values of L*, a*, and b* according toEquation 3. Here, a difference of approximately ≤1.5 was accepted as agood color match. Values of ΔE were reported for full coating stacks(Table 13).

ΔE=√{square root over ((ΔL*)²+(Δa*)²+(Δb*)²)}  Equation 3

TABLE 13 ΔE Values for Coating Stacks Coating stack color ΔE C-R 0.8C-DR 1.0 C-BK 1.2 C-BL 0.4 C-DBL 0.8

Example 11

Coatings were characterized by the follow methods:

Conventional and near-IR reflective coating stacks described in Example5, prepared according to Examples 6-9 and characterized according toExamples 10 and 11 were used for total solar reflectance measurements. AUV-Vis-NIR Lambda 950 spectrophotometer was used to measure the percentreflection of samples across near-IR wavelengths (700 nm-2500 nm) andalso specifically at 905 nm, which is the wavelength used by certainLIDAR detectors (Table 14).

TABLE 14 Reflectance Measurements at Near-IR Wavelengths PercentReflectance Coating Total Near-IR color (700-2500 nm) 905 nm C-R1 8.015.2 C-R2 36.4 79.4 C-DR1 3.8 6.9 C-DR2 35.4 80.1 C-BK1 2.0 3.7 C-BK232.3 77.0 C-BL1 3.9 8.5 C-BL2 19.6 30.2 C-DBL1 3.6 7.6 C-DBL2 20.7 24.1

Conventional and near-IR reflective coating stacks described in Example5, prepared according to Examples 6-9 and characterized according toExamples 10 and 11 were used for LIDAR testing. Complete coating stacks(C-) were referred to by color (R, DR, BK, BL, and DBL) and whether theywere a conventional or near-IR reflective system (1 or 2, respectively;Table 15). Three different LIDAR units were used to measure the outdoormaximum detection range of the coated 4″×12″ panels. These includedVelodyne VLP-16, Velodyne HDL32e, and Velodyne HDL64-S2 which usedVeloview 3.1.1 software to record collected data points (Table 15).

TABLE 15 LIDAR Unit Properties Velodyne Velodyne Velodyne PropertyVLP-16 HDL 23e HDL64-S2 Laser wavelength (nm) 905 903 905 Measurementaccuracy (mm) +/−30 mm +/−20 mm +/−20 mm Maximum range 100  70 120

Panels were mounted on a stand where the 12″ side was oriented parallelto the ground (see FIG. 1). Each panel was measured outdoors at twodifferent angles of incidence relative to the LIDAR source. Panels werepositioned at an angle that was normal to the LIDAR unit (90°) orpositioned at a 30° angle relative to the normal angle (see FIG. 2).During each measurement, the mounted panel was positioned within line ofsight of the LIDAR unit and was moved incrementally further from theunit until the return intensity of the signal from the panel was nolonger detected using the Veloview 3.1.1 software. The average ambientillumination outdoors during testing was in the range of 60 lux-80,000lux.

The maximum detection range for each LIDAR unit at each angle ofillumination is reported in Table 16. The largest increase in detectionrange was achieved by red, dark red, and black colored near-IRreflective coating stacks (C-R2, C-DR2, and C-BK2). These coating stacksincreased detection range up to a maximum of 56% depending on the LIDARunit and angle of incidence. Blue and dark blue near-IR reflectivecoating stacks (C-BL2 and C-DBL2) also increased detection range, andthese coating stacks increased detection range up to a maximum of 36%.The average percent improvement in detection range that was achievedusing near-IR reflective coating stacks is reported in Table 17.

TABLE 16 Maximum Detection Range (m) of Coating Stacks Measured by LIDARUnits at Two Angles of Incidence Coating Velodyne VLP-16 Velodyne HDL32eVelodyne HDL64-S2 Color 0° 30° 0° 30° 0° 3° C-R1 60.2 53.4 70.1 67.185.3 82.3 C-R2 83.8 65.2 109.1 83.6 119.1 104.9 C-DR1 60.5 55.6 70.766.6 84.9 83.9 C-DR2 76.5 72.5 89.2 82.7 95.8 109.1 C-BK1 61.7 58.1 67.164.5 85.6 79.7 C-BK2 81.1 74.0 97.6 84.4 119.1 101.6 C-BL1 73.0 54.278.0 59.9 84.5 78.0 C-BL2 72.9 63.4 80.8 70.4 88.2 91.5 C-DBL1 60.6 53.768.3 68.6 82.6 79.5 C-DBL2 71.1 70.2 78.0 70.5 87.8 90.0

TABLE 17 Average Percent Improvement in Detection Distance Achieved byNear-IR Reflective Coating Stacks at 905 nm Wavelength Coating stackcolor Average % Improvement C-R2 35% C-DR2 25% C-BK2 34% C-BL2 15%C-DBL2 22%

Example 12

Conventional and improved near-IR reflective coating stacks, whichreduce transmission of light through the coating stack and demonstrate amore jet black color, were designed and prepared as follows:

Coatings used in conventional systems contained carbon black pigment.Gray colored primers were shaded with TiO₂ and carbon black tint pastes.A mid-gray colored conventional primer formula (Primer MG1) wereprepared as described in Example 5 of U.S. Pat. No. 7,959,981 withmodification in levels of carbon black tint that were adjusted toachieve a mid-gray color (Table 18). Black colored conventional andnear-IR transparent basecoat formulas (BK1 and BK2, respectively) wereprepared according to Example 7.

Near-IR reflective coating stacks contained no carbon black in any ofthe coating layers. Mid-gray and white colored near-IR reflectiveprimers (Primer MG2 and Primer W 1, respectively) were prepared (Table18). Mid-gray colored primers were shaded with TiO₂ and near-IRtransparent black tint pastes prepared in Example 4. Near-IR reflectivemid-gray primers were prepared as described in Example 5 of U.S. Pat.No. 7,959,981 without adding carbon black tint and instead addingnear-IR transparent black tint pastes prepared in Example 4 to achieve acolor that was a match to the conventional mid-gray primer. Whiteprimers were also prepared (as described in Example 5 of U.S. Pat. No.7,959,981 with a modification that eliminated use of carbon black tintpaste). Compared to a white primer containing only TiO₂, the near-IRreflective gray primers maintain high near-IR reflection and alsoimprove protection of underlying coating layers from transmission ofdamaging wavelengths of light (400 nm-450 nm). Aesthetics of the near-IRreflective coating stack are also improved because a gray primer hasless visual contrast with a dark colored topcoat if the topcoat ischipped or damaged to reveal the primer layer underneath.

Black colored topcoats used in near-IR reflective coating stacks (BK2)contained near-IR transparent colored tint pastes from Example 4 (PasteTB1 and Paste TB2) instead of carbon black tint paste. Black coloredtopcoats used in conventional coating stacks (BK1) contained carbonblack tint paste. Basecoat mixtures were prepared as described inExample 7.

TABLE 18 Primer Formulas (Reference Example 5 of U.S. Pat. No. 7,959,981B2) Primer MG1 Primer MG2 Primer W1 Component (g) (g) (g) Isopropylacetate 121.7 120.8 122.6 RESIMENE ® R-718¹⁸ 104.6 103.8 105.3 PolyesterPolyol¹⁹ 146.9 145.8 147.9 White Pigment Dispersion²⁰ 122.9 121.9 123.7Flow Additive²¹ 0.5 0.5 0.5 Black Pigment Dispersion²² 3.4 0.0 0.0 TB1(Example 4) 0.0 5.7 0.0 TB2 (Example 4) 0.0 1.1 0.0 Yellow PigmentDispersion²³ 0.0 0.5 0.0 Total formula weight 500.0 1000.0 500.0 ¹⁸Usedaccording to Example 5 of U.S. Pat. No. 7,959,981 B2;Melamine-formaldehyde resin solution commercially available from INEOSMelamines (Rolle, Switzerland) ¹⁹Prepared according to Example 5 of U.S.Pat. No. 7,959,981 B2; A polyester resin comprising 18% neopentylglycol, 16% neopentyl glycol hydroxyl pivalate, 8% trimethol propane, 8%adipic acid, 16% e-caprolactone, and 34% isophthalic acid in n-butylacetate solvent at 69% solids and approximately 4,800 Mw ²⁰Usedaccording to Example 5 of U.S. Pat. No. 7,959,981 B2; titanium dioxidepigment dispersion in polyester polyol resin, PPG Industries, Inc.(Pittsburgh, PA) ²¹Used according to Example 5 of U.S. Pat. No.7,959,981 B2; Poly butyl acrylate flow additive commercially availablefrom DuPont (Wilmington, DE) ²²Used according to Example 5 of U.S. Pat.No. 7,959,981 B2; carbon black pigment dispersion in polyester polyolresin, PPG Industries, Inc. (Pittsburgh, PA) ²³Yellow iron oxide pigmentdispersion in polyester polyol resin, PPG Industries, Inc. (Pittsburgh,PA)

In both conventional and near-IR reflective coating stacks, clearcoat(TMAC9000FR, commercially available from PPG Industries, Inc.(Pittsburgh, Pa.)) was used directly for application over the coloredtopcoats.

Example 13

Conventional and improved near-IR reflective coating formulas preparedin Example 12 were spray-applied as coating stacks and cured accordingto U.S. Pat. No. 7,959,981.

Conventional coating stacks included mid-gray primer (Primer MG1), blackbasecoat (BK1), and clearcoat (TMAC 9000FR).

Near-IR coating stacks included near-IR reflective mid-gray primer(Primer MG2), near-IR transparent black basecoat (BK2), and clearcoat(TMAC 9000FR). In a second example, near-IR coating stacks includednear-IR reflective white primer (Primer W1), near-IR transparent blackbasecoat (BK2), and clearcoat (TMAC 9000FR).

All coating stacks for reflectance measurements were applied to coldrolled steel (CRS) panels pretreated with zinc phosphate (C700),Chemseal 59 rinse (C59), and ED6465 gray cationic electrocoat weresupplied by ACT (Hillsdale, Mich.).

All coatings stacks for transmission measurements required preparationas free films. This was accomplished by first applying TEDLAR® film(commercially available from DuPont (Wilmington, Del.)) to a cold rolledsteel (CRS) panel supplied by ACT (Hillsdale, Mich.). The TEDLAR® filmswere smoothed and taped on the panel, then baked in a convection ovenfor 30 minutes at 140° C. Coatings stacks could then be applied andcured as specified and be completely released from the TEDLAR® film.

Example 14

Primer and basecoat formulas prepared in Example 13 were measured foropacity according to Example 9.

Dry film thicknesses for coatings described in Example 12 used toachieve opacity are reported in Table 19.

TABLE 19 Dry Film Thickness Values to Achieve Coating Opacity Dry filmthickness Coating Number of coats (μm) Primer MG1 1 23 Primer MG2 1 25Primer W1 1 24 BK1 1 12 BK2 1 8

Example 15

Coatings were color matched according to Example 10.

Mid-gray conventional and near-IR reflective primers prepared in Example12 (Primer MG1 and Primer MG2, respectively) were evaluated in colorspace to determine a visual color match. Conventional and near-IRtransparent black basecoats prepared in Example 12 (BK1 and BK2,respectively) were evaluated in color space to determine a visual colormatch. In each case, basecoats were measured after clearcoatapplication, as designated by “C-BK1” for clearcoated conventionalbasecoat and “C-BK2” for clearcoated near-IR basecoat. Delta E valuesbetween coating stacks are represented as “Primer MG1” and “Primer MG2”,as well as “C-BK1” and “C-BK2” in Table 20.

TABLE 20 ΔE Values for Coating Stacks Coatings Compared ΔE Primer MG1 toPrimer MG2 0.9 C-BK1 to C-BK2 1.1

Example 16

The transmission of coating stacks prepared as free films in Example 13were characterized:

Percent light transmission was measured using a Perkin Elmer Lambda950UV-vis spectrometer from 200 nm to 2500 nm. The total percent oftransmitted light between 400 nm and 450 nm for each coating stack isreported in Table 21. Conventional and near-IR reflective coating stacks(primer, basecoat, clearcoat) are represented as “Primer MG1-BK1”,“Primer MG2-BK2”, and “Primer W1-BK2”.

TABLE 21 Transmission Measurements of Full Coating Stacks Total PercentTransmission Coating Stack Description (400-450 nm) Primer MG1-BK1Conventional with mid-gray primer 0.04 Primer MG2-BK2 Near-IR withmid-gray primer 0.37 Primer W1-BK2 Near-IR with white primer 7.95

Example 17

The near-IR reflection of coating stacks were characterized according toExample 11.

Conventional and near-IR reflective coating stacks described in Example12, prepared according to Example 13, and characterized according toExamples 15 and 16 were used for total solar reflectance measurements. AUV-Vis-NIR Lambda 950 spectrophotometer was used to measure the percentreflection of samples across near-IR wavelengths (700 nm-2500 nm) andalso specifically at 905 nm, which is the wavelength used by certainLIDAR detectors. Conventional and near-IR reflective coating stacks(primer, basecoat, clearcoat) are represented as “Primer MG1-BK1”,“Primer MG2-BK2”, and “Primer W1-BK2”, and described in Table 22.

TABLE 22 Reflectance Measurements of Full Coating Stacks at Near-IRWavelengths Percent Reflectance Total Near-IR Coating Stack Description(700-2500 nm) 905 nm Primer MG1-BK1 Conventional with mid-gray 3.5 3.6primer Primer MG2-BK2 Near-IR with mid-gray 50.2 68.7 primer PrimerW1-BK2 Near-IR white primer 44.6 62.1

Example 18

A white primer was prepared using the ingredients and amounts listed inTable 23.

TABLE 23 White Primer WP Component (kg) EPON 1001-T-75²⁴ 18.6Anti-Terra-U²⁵ 0.5 SILQUEST ® A-187²⁶ 0.6 TIOXIDE ® TR92²⁷ 50.3 n-Butylalcohol 3.6 Aromatic hydrocarbon mixture - 100 type 23.9 2-Butoxyethylacetate 2.5 ARADUR ® 115 × 70²⁸ 7.3 Total formula weight 107.3²⁴Commercially available from Hexion (Columbus, OH) ²⁵Commerciallyavailable from BYK Additives and Instruments (Wesel, Germany)²⁶Commercially available from Momentive Performance Materials(Waterford, NY) ²⁷Commercially available from Huntsman Corporation (TheWoodlands, TX) ²⁸Commercially available from Huntsman Corporation (TheWoodlands, TX)

All materials except for the ARADUR® 115×70 were weighed into a glassjar. Liquid components, such as resin, liquid additives, and solventwere added first and hand-mixed before the addition of solid pigments.Zirconox media (1.2 mm-1.7 mm) was then added to the jar at a 1:1 massratio. The jar was sealed with a lid and tape and then placed on a LauDisperser DAS 200 with a dispersion time of 2 hours. The finaldispersion had a Hegman gauge value around 7. Aradur® 115×70polyamidoamine hardener was then added and mixed in by hand. Acetone wasadded as a thinner to reach a spray viscosity of 30-60 cP on theBrookfield viscometer. The primer was then ready to spray.

Example 19

Near-IR transparent tint pastes were prepared using the ingredients andamounts listed in Table 24.

TABLE 24 Near-IR Transparent Tint Pastes TP1 (B31) TP2 (B32-P) TP3(B32-H) Component (kg) (kg) (kg) Acrylic Dispersant²⁹ 35.6 35.2 38.3n-Butyl Acetate Urethane Grade 6.7 0 52.2 n-Butyl Propionate 48.0 55.1 0HELIOGEN ® Blue L 6700 F³⁰ 1.2 0 9.5 PALIOGEN ® Black L 0086³¹ 8.5 9.7 0Total formula weight 100.0 100.0 100.0 ²⁹Acrylic dispersant used isdescribed in U.S. Pat. No. 8,129,466. ³⁰Commercially available from BASFCorporation (Ludwigshafen, Germany) ³¹Commercially available from BASFCorporation (Ludwigshafen, Germany)

Tint pastes TP1, TP2, and TP3 were prepared by combining componentsshown in Table 24, in order. The tint paste was dispersed with Potter'sGlass Spheres P2227 grind media for 16 hours using a Lau disperser DAS200. The media was sieved to remove fractions smaller than 75 micronsand loaded at 200% of sample weight. The media was removed from grindpaste via filtration to give the final tint pastes.

Example 20

Near-IR transparent single-stage Topcoat A components were preparedusing the components listed in Table 25.

TABLE 25 Near-IR Transparent Single-Stage Topcoat A Components TCA1(B31) TCA2 (B32) Component (kg) (kg) TP1 (from Example 19) 52.1 0 TP2(from Example 19) 0 45.5 TP3 (from Example 19) 0 6.6 Acrylic Resin³²13.6 13.6 Polyester Resin³³ 16.1 16.1 Aromatic Solvent 100 Type 1.4 1.4n-Butyl Acetate Urethane Grade 3.7 3.7 Polyester Resin³⁴ 12.6 12.6BYK-300³⁵ 0.1 0.1 TINUVIN ® 123³⁶ 0.4 0.4 Total formula weight 100.0100.0 ³²Acrylic resin used is described in U.S. Pat. No. 6,306,505Example A ³³Polyester resin is a polyester from Cardura E 10-P(commercially available form Hexion (Columbus, OH)), phthalic anhydrideand trimethylol propane with a 70% solids content in methyl etherpropylene glycol acetate/Aromatic solvent 100 type (83.5/16.5); with ahydroxyl value of 54 mg KOH/g; with an acid value of 9.5 mg KOH/g; witha Gardner viscosity of Z ³⁴Saturated hydroxylated polyester resinavailable from Galstaff MultiResine (Mornago, Italy) ³⁵Commerciallyavailable from BYK Additives and Instruments (Wesel, Germany)³⁶Commercially available from BASF Corporation (Ludwigshafen, Germany)

Tint pastes were then combined with the liquid formulation componentsand complete Component A formulations were then shaken on the Laudisperser for 30 minutes. Commercial PPG medium solids hardener F3270and medium reducer F3330 were mixed with these Component A formulations,as well as with DELFLEET® Evolution single-stage topcoat FDG9000Component A using volume ratios shown in Table 26.

TABLE 26 Volume Ratios for Single-Stage Topcoats SSTC1, SSTC2, andFDG9000 Component SSTC1 SSTC2 FDG9000 TCA1 4 0 0 TCA2 0 4 0 DELFLEET ®Evolution FDG9000 0 0 4 Component A ³⁷ Medium Solids Hardener F3270 1 12 Medium Thinner F3330 1 1 1 ³⁷ Commercially available from PPGIndustries, Inc. (Pittsburgh, PA)

Example 21

Conventional and near-IR reflective coating stacks were prepared usingthe components listed in Table 27.

TABLE 27 Coating Stack Near-IR Conventional Reflective Component CoatingStack Coating Stack Substrate ACT CRS³⁸ ACT CRS³⁸ Primer WP³⁹ WP³⁹Single-Stage Topcoat DELFLEET ® Evolution SSTC1 or SSTC2 FDG9000⁴⁰³⁸Commercially available from ACT (Hillsdale, MI) ³⁹White primer fromExample 18 ⁴⁰Polyurethane single-stage topcoat commercially availablefrom PPG Industries Inc. (Pittsburgh, PA)

Prior to applying the coating composition, clean only cold-rolled steelsubstrate panels were cleaned with OneChoice SXA330 degreaser. A tackrag was run over the panels prior to spraying. The white primer was thenspray applied to the prepared substrate panels using an air atomizedHVLP gun with a 1.8 mm spray tip. A flash time of 10 minutes in betweencoats was used and coated panels were allowed to stand under ambientconditions for at least an hour. The dry film thickness (DFT) of theprimer was approximately 2.3 mils.

Topcoats were applied using a HVLP spray gun with a 1.4 mm tip at apressure of 30 psi. Two coats were applied for a DFT of approximately1.5 mils. Coatings were ambient cured.

Example 22

Coatings described in Example 20 were spray applied over black and whiteopacity charts (BYK Leneta) according to Example 21 and measured foropacity according to Example 9. Dry film thicknesses for coatingsdescribed in Example 20 used to achieve opacity were 1.5 mils.

Example 23

Coatings from Example 22 were color matched according to Example 10. ABYK-mac i spectrophotometer was used to evaluate conventional andnear-IR systems. Values of ΔE were reported for single-stage topcoatsfrom Example 20 (Table 28).

TABLE 28 ΔE Values for Topcoats Topcoats ΔE SSTC1 1.0 SSTC2 1.1

Example 24

The near-IR reflection of coating stacks were characterized according toExample 11:

Conventional and near-IR reflective coating stacks described in andprepared according to Example 21 and characterized according to Examples22 and 23 were used for total solar reflectance measurements.Conventional and near-IR reflective coating stacks (primer, topcoat) arerepresented as “WP-SSTC1” and “WP-SSTC2” and described in Table 29.

TABLE 29 Reflectance Measurements of Full Coating Stacks at Near-IRWavelengths Percent Reflectance Total Near-IR Coating Stack Description(700-2500 nm) 905 nm WP-SSTC1 Near-IR with white primer 53.9 77.9WP-SSTC2 Near-IR with white primer 56.1 80.8 WP-FDG9000 Conventionalwith white 3.6 3.7 primer

Example 25

Coating compositions were prepared including the components listed inTable 30. For each coating composition, the component or componentslisted as 1a-1k were premixed to form the pigmented base coatingcomponent. Components 2 and 3, the activator and thinner, were thenadded and the coating composition mixed to uniformity just prior toapplication.

TABLE 30 Comp. Comp. Comp. Comp. Comp. Component Grey 1 Grey 2 Grey 3Grey 4 Grey 5 White 1 White 2 Grey 1 Purple 1 Green 1 1a Untinted WhiteBase⁴¹ 58.62 58.34 — — 49.81 — — — 48.59 48.4  1b IR Transparent Black0.5  0.78 — —  9.38 — — — — — Base⁴² 1c Yellow Tint Base⁴³  0.04  0.04 —— — — — — — — 1d Red Tint Base⁴⁴  0.01  0.01 — — — — — — — — 1e TintedGrey Base⁴⁵ — — 59.17 — — — — — — — 1f Tinted Grey Base⁴⁶ — — — 59.19 —— — — — — 1g Tinted White Base⁴⁷ — — — — — 59.17 — — — — 1h Tinted WhiteBase — — — — — — 59.19 — — — (with Carbon Black)⁴⁸ 1i Tinted Grey Base —— — — — — — 59.19 — — (with Carbon Black)⁴⁹ 1j IR Transparent — — — — —— — —  9.15 — Purple⁵⁰ 1k IR Transparent — — — — — — — — —  9.11 Green⁵¹2 Activator⁵² 22.98 22.98 22.98 22.97 22.97 22.98 22.97 22.97 23.7923.92 3 Thinner⁵³ 17.85 17.85 17.85 17.84 17.84 17.85 17.84 17.84 18.4718.57 ⁴¹Pigmented polyol base component commercially available from PPGAerospace PRC-DeSoto as DESOTHANE ® HS CA8000/BAC7067 (Sylmar, CA).⁴²Pigmented polyol base component commercially available from PPGAerospace PRC-DeSoto as DESOTHANE ® HS CA8000/SR8000 (Sylmar, CA).Includes a mixture of Components 1j and 1k. ⁴³Pigmented polyol basecomponent at approximately 76% solids in solvent and a P:B = 1.39 withbinder including a blend of approximately 68% polyester polyol (100%active, hydroxyl number = 230) and 32% polycaprolactone (100% active,hydroxyl value = 218), pigments including approximately 44% yellow ironoxide (PY42) and 56% barium sulfate and a mixture of additives such asdispersants, UV protection package, anti-settling modifiers and othercommon additives known to those familiar with the art (Sylmar, CA).⁴⁴Pigmented tint base component at approximately 73% solids in solventand a P:B = 1.03 with binder includin a blend of approximately 68%polyester polyol (100% active, hydroxyl number = 230) and 32%polycaprolactone (100% active, hydroxyl value = 218), pigments includinapproximately 24% quinacridone red (PV19) and 76% barium sulfate and amixture of additives such as dispersants, UV protection package,anti-settling modifiers and other common additives known to thosefamiliar with the art (Sylmar, CA). ⁴⁵Pigmented polyol base componentcommercially available from PPG Aerospace PRC-DeSoto as DESOTHANE ® HSCA8000/SR1343 (Sylmar, CA). Component 1e included a mixture ofComponents 1a and 1b. ⁴⁶Pigmented polyol base component commerciallyavailable from PPG Aerospace PRC-DeSoto as DESOTHANE ® HS CA8000/BAC2001(Sylmar, CA). Component 1f included a mixture of Components 1a and 1b.⁴⁷Pigmented polyol base component commercially available from PPGAerospace PRC-DeSoto as DESOTHANE ® HS CA8000/SR1408 (Sylmar, CA).⁴⁸Pigmented polyol base component commercially available from PPGAerospace PRC-DeSoto as DESOTHANE ® HS CA8000/BAC70846 (Sylmar, CA).Component 1h included carbon black. ⁴⁹Pigmented polyol base componentcommercially available from PPG Aerospace PRC-DeSoto as DESOTHANE ® HSCA8000/BAC707 (Sylmar, CA). Component 1i included carbon black.⁵⁰Pigmented dispersion component prepared in a manner consistent withU.S. Pat. No. 9,057,835 B2 Example 2. Component 1j included TiO₂.⁵¹Pigmented dispersion component prepared in a manner consistent withU.S. Pat. No. 9,057,835 B2 Example 6. Component 1j included TiO₂.⁵²Isocyanate oligomer based hardener component commercially availablefrom PPG Aerospace PRC-DeSoto as DESOTHANE ® HS CA8000B Activator(Sylmar, CA). ⁵³Solvent based thinner component commercially availablefrom PPG Aerospace PRC-DeSoto as CA8000C (Sylmar, CA).

Example 26

Table 31 compares several of the coating compositions prepared inExample 25 (the grey primer made using a combination of infraredtransparent black pigments (Grey 3) and the grey primer made usingcarbon black (Comp. Grey 1)).

TABLE 31 Grey 3 Comp. Grey 1 % Total Solar Reflectance 72 43 Differencein % TSR 29 — % Improvement in % TSR 40 — Maximum Temperature Measured153.9 (67.7) 173.0 (78.3) Under Heat Lamp ° F. (° C.) Difference inTemperature ° F. (° C.)  19.1 (10.6) — % Improvement in Maximum 11 —Temperature

The samples from Table 31 were prepared as follows: 1 mil (25.4 microns)of a carbon black paint (commercially available from PPG AerospacePRC-DeSoto as DESOTHANE® HS CA8000/BAC701 (Sylmar, Calif.)) was appliedto 3″×6″ panels of 2024 T3 aluminum to mimic the near-IR absorption of acarbon fiber composite substrate. On top of this was applied 0.8 mils(20.32 microns) of a chrome free primer (commercially available asDESOPRIME® CF/CA7502A from PPG Aerospace PRC-De-Soto (Sylmar, Calif.)).The coating compositions were spray applied thereover by hand using aBinks Mach 3 HVLP type spray gun and a 95AS spray cap to a dry filmthickness that provided full hiding. Percent Total Solar Reflectance (%TSR) was measured using a LAMBDA 950 S ultraviolet/visible/near-IRspectrophotometer (PerkinElmer®) following ASTM E903-12.

The maximum temperature reached under a heat lamp was also measured.This was carried out using a testing apparatus defined in ASTM B4803-10including an insulated wooden box, IR lamp and a digital thermometerusing a Type J thermocouple. The two panels were placed side-by-side,but not in contact, 15.5 inches directly under the IR lamp and monitoredfor temperature until both panels reached a maximum temperature, whichdid not increase any further. Comp. Grey 1 reflected 43% of the totalsolar radiation, whereas Grey 3 reflected 72%, for a relative increasein performance of 44%. The samples coated with Grey 3 had a maximumtemperature that was 19.1° F. (10.6° C.) less than Comp. Grey 1.

Example 27

Several of the coating compositions prepared in Example 25 were appliedto full hiding over a byko-chart Brushout 5DX Card (Byk-Gardner catalogNo. 2856). The samples were then characterized for CIELAB color using anintegrated sphere with D65 Illumination and 10° observer with specularincluded on a Datacolor 600™ spectrophotometer to measure L*, a*, b*,C*, h°, and ΔE* color values. In the CIELAB color system, L* representslightness/darkness on a scale of 0=pure black to 100=diffuse white, a*represents the balance of green −a* to red+a*, b* represents the balanceof blue −b* to yellow+b*, C* represents chroma, and h° represents hueangle. The ΔE* value represents the three dimensional color modeldifference between two colors. Table 32 shows the CIELABcharacterizations for the prepared samples.

TABLE 32 Comp. Comp. Grey 5 Purple 1 Green 1 Absolute L* 78.11 67.7280.97 Absolute a* −0.82 9.32 −3.97 Absolute b* −3.73 −16.91 −0.32Absolute C* 3.82 19.31 3.98 Absolute h ° 258 299 185 ΔL* — −10.39 2.86ΔC* — 15.49 0.16 Δh ° — 41 −73 ΔE* (CIE76) — 19.61 5.45

The grey color in Grey 5 (from Example 25) was achieved by blending twoinfrared transparent pigments (perylene pigments) as demonstrated by themeasurements included in Table 32. Grey 5 blended a green-shade perylenepigment and a purple-shade perylene pigment.

Each of the individual perylene pigments in Comp. Purple 1 and Comp.Green 1 utilized alone at a high enough concentration and applied at asuitable dry film thickness yields a coating that appears black to thehuman eye. However, when the perylene pigment is utilized in combinationwith titanium dioxide (as in Comp. Purple 1 and Comp. Green 1 of Example25) in a single coating, one IR transparent black pigment results in apurple shade, and the other results in a green shade. This isillustrated by comparing Grey 5 with Comp. Purple 1 and Comp. Green 1.Grey 5 is a neutral grey made using a blend of the two IR transparentblack pigments. For Comp. Purple 1 and Comp. Green 1, that blend wasreplaced with an equivalent amount by weight of just the individualpigment tints.

Table 32 shows that there is a difference in color between Grey 5 andComp. Purple 1, with a ΔE of 19.61 and a difference in color betweenGrey 5 and Comp. Green 1, with a ΔE of 5.45. The L*, a*, and b* valuesindicate that Grey 5 exhibits an off-white or grey shade, while the L*and h° indicate that Comp. Purple 1 exhibits a purple shade and Comp.Green 1 exhibits a green shade.

Example 28

Several coating compositions from Example 25 were applied over adifferent substrate and coating stack as follows. An untinted whitebasecoat (commercially available from PPG Aerospace PRC-DeSoto asDESOTHANE® HS CA8000/BAC7067 (Sylmar, Calif.)) was sprayed over analuminized paper (commercially available as part 20PAP10X15SV fromAlufoil Products Co., Inc. (Hauppauge, N.Y.)). The coating compositionswere spray applied thereover by hand using a Binks Mach 3 HVLP typespray gun and a 95AS spray cap to a dry film thickness that providedfull hiding. Hiding was determined using ASTM D6762 on Leneta black andwhite hide strips. The cured film coating density for the samples inTable 33 was 1.57 g/cc. The CIELAB color characterizations for thesesamples, % TSR, and the thickness required for full hiding are shown inTable 33.

TABLE 33 Comp. Comp. White 2 Grey 1 Grey 1 Grey 2 Grey 3 Grey 4 AbsoluteL* 95.59 78.07 93.03 91.71 90.34 77.80 Value Absolute a* −0.72 −1.88−0.88 −0.87 −0.84 −1.88 Value Absolute b* 1.10 0.69 0.17 −0.40 −0.820.69 Value Absolute C* 1.31 2.00 0.90 0.96 1.17 2.00 Absolute h° 123 160169 205 224 160 % Total Solar 84 44 82 80 79 69 Reflectance Dry Film2.65 1.45 2.45 2.05 1.53 1.45 Thickness of Coating Required to ProvideFull Hiding (mils) Weight of Cured 38 21 35 29 22 21 Coating at FullHiding Thickness to Cover Wing (kg)

Given an aircraft wing with a surface area of 360.5 m², typical for aBoeing 787 type aircraft using carbon fiber composite materials, thisthin layer of coating would result in a range of 21-38 kg of paint onthe aircraft wing, as shown in Table 33. In order to maximize the % TSR,it would be necessary to apply a thicker layer and incur a significantweight penalty. Thus, Comp. White 2, while having the best % TSR, wouldadd a prohibitive amount of weight. Meanwhile, Comp. Grey 1 would havethe lowest weight, but has a comparatively low % TSR.

Example 29

The samples shown in Table 34 (using coating compositions from Example25) were prepared as described in Example 26, with a black coatingfollowed by a primer coating and then finally Grey 3 or Comp. White 1.An additional sample was prepared by spraying Comp. White 1 as thehighly solar reflective under-layer while Grey 3 was sprayed on top ofit as the pigmented topcoat, resulting in a two layer coating system.Hiding was determined using ASTM D6762 on Leneta black and white hidestrips. Results from these samples are shown in Table 34.

TABLE 34 Comp. Grey 3 over Grey 3 White 1 Comp. White 1 Single Layer TwoLayers % TSR 72 80 75 Dry Film Thickness of Coating 1.8 2.8 4.0 Requiredto Provide Full Hiding (mils) Cured Film Coating Density (g/cc) 1.571.57 1.57 Approximate Surface Area of Boeing 360.5 360.5 360.5 787 Wing(m²) Weight of Cured Coating at Full 25.9 40.3 57.5 Hiding Thickness toCover Wing (kg) Weight Savings vs. Two Layers (kg) 31.6 — — % WeightSavings 55 — —

Comparing the % TSR, using the two layer system does result in anincrease from Grey 3 at 72 to the two layer system at 75. However withthe two layer system, the total thickness of the two layers is 4.0 milscompared to 1.8 mils for Grey 3. Therefore, Grey 3 demonstrates a weightsaving of 55% over the Gray 3 over Comp. White 1 without a significantloss of % TSR.

The present invention further includes subject matter of the followingclauses.

Clause 1: A method for increasing a detection distance of a surface ofan object illuminated by near-IR electromagnetic radiation, comprising:(a) directing near-IR electromagnetic radiation from a near-IRelectromagnetic radiation source towards an object at least partiallycoated with a near-IR reflective coating that increases a near-IRelectromagnetic radiation detection distance by at least 15% as measuredat a wavelength in a near-IR range as compared to the same object coatedwith a color matched coating which absorbs more of the same near-IRradiation, wherein the color matched coating has a ΔE color matchedvalue of 1.5 or less when compared to the near-IR reflective coating, asmeasured using an integrating sphere with D65 Illumination, 10° observerwith specular component included; and (b) detecting reflected near-IRelectromagnetic radiation reflected from the near-IR reflective coating.

Clause 2: The method of clause 1, wherein the near-IR reflective coatingexhibits a CIELAB L* value of 35 or less as measured using anintegrating sphere with D65 Illumination, 10° observer with specularcomponent included.

Clause 3: The method of clause 1 or 2, wherein the near-IR reflectivecoating comprises at least one visibly-absorbing near-IR transparentpigment and/or dye.

Clause 4: The method of any of the preceding clauses, wherein thenear-IR reflective coating is substantially free of carbon black.

Clause 5: The method of any of the preceding clauses, wherein thenear-IR reflective coating comprises a first coating layer and a secondcoating layer.

Clause 6: The method of clause 5, wherein the first coating layercomprises at least one visibly-absorbing near-IR transparent pigmentand/or dye and the second coating layer comprises at least one near-IRreflective pigment.

Clause 7: The method of clause 5 or 6, wherein the second coating layerunderlies at least a portion of the first coating layer.

Clause 8: The method of any of clauses 5-7, wherein the second coatinglayer comprises: a film-forming resin; a plurality of near-IRtransparent pigments and/or dyes dispersed in the film-forming resin,the plurality of near-IR transparent pigments and/or dyes comprising afirst perylene pigment and a second perylene pigment different from thefirst perylene pigment; and a near-IR reflective pigment dispersed inthe film-forming resin, the near-IR reflective pigment different fromthe first perylene pigment and the second perylene pigment, wherein thesecond coating layer exhibits an off-white or grey color, and whereinthe second coating layer is substantially free of carbon black.

Clause 9: The method of any of clauses 5-8, wherein the second coatinglayer comprises: a film-forming resin; a plurality of colorantsdispersed in the film-forming resin, the plurality of colorantscomprising a near-IR transparent pigment or dye, wherein the near-IRtransparent pigment or dye comprises a first near-IR transparent pigmentor dye and a second near-IR transparent pigment or dye different fromthe first near-IR transparent pigment or dye; and a near-IR reflectivepigment dispersed in the film-forming resin, the near-IR reflectivepigment different from the first near-IR transparent pigment or dye andthe second near-IR transparent pigment or dye, wherein the secondcoating layer exhibits an off-white or grey color, and wherein thesecond coating layer is substantially free of carbon black.

Clause 10: The method of any of the preceding clauses, wherein theobject is a vehicle, road, road traffic safety product, signage, orclothing.

Clause 11: The method of any of the preceding clauses, wherein thenear-IR reflective coating reflects at least 20% of the radiation at awavelength in the near-IR range directed in step (a) at the object.

Clause 12: The method of any of the preceding clauses, wherein thenear-IR reflective coating reflects electromagnetic radiation having atleast one wavelength in the range of 700 nm to 2500 nm.

Clause 13: The method of any of the preceding clauses, wherein thenear-IR reflective coating reflects electromagnetic radiation having atleast one wavelength in the range of 900 nm to 1600 nm.

Clause 14: The method of any of clauses 5-13, further comprising atransparent clearcoat layer positioned over at least a portion of thefirst coating layer.

Clause 15: The method of any of clauses 10-14, wherein the object is avehicle and the near-IR reflective coating covers at least 10 percent ofan exterior surface area of the vehicle.

Clause 16: The method of any of the preceding clauses, wherein thenear-IR electromagnetic radiation source and near-IR detector arecoupled to a vehicle.

Clause 17: The method of any of the preceding clauses, wherein thenear-IR reflective coating is capable of increasing the near-IRelectromagnetic radiation detection distance by at least 25%.

Clause 18: The method of any of clauses 8-17, wherein the first perylenepigment comprises a green-shade perylene pigment and the second perylenepigment comprises a purple-shade perylene pigment.

Clause 19: The method of clause 8-18, wherein the second coating layerexhibits the following CIELAB values using an integrating sphere withD65 Illumination, 10° observer with specular component included: a L*value ranging from 40-95; an a* value ranging from −2 to 2; and a b*value ranging from −6 to 6.

Clause 20: The method of any of clauses 8-19, wherein the near-IRreflective pigment comprises titanium dioxide.

Clause 21: The method of clause 20, wherein the titanium dioxide isdispersed in the film-forming resin in powder form.

Clause 22: The method of any of clauses 8-21, wherein the second coatinglayer fully hides a surface of the object at a dry film thickness ofless than or equal to 2.5 mils.

Clause 23: The method of any of the preceding clauses, wherein theobject at least partially coated with the near-IR reflective coatingincreases the near-IR electromagnetic detection distance by at least15%, as measured at 905 nm.

Clause 24: The method of any of the preceding clauses, wherein theobject at least partially coated with the near-IR reflective coatingincreases the near-IR electromagnetic detection distance by at least 15%as measured at 1550 nm.

Clause 25: The method of any of the preceding clauses, wherein thenear-IR reflective coating comprises at least one near-IR fluorescingpigment and/or dye.

Clause 26: The method of any of clauses 5-25, wherein the first and/orsecond coating layer comprises at least one near-IR fluorescing pigmentand/or dye.

Clause 27: The method of any of clauses 5-26, wherein the first coatinglayer is a top layer of the near-IR reflective coating.

Clause 28: A system for detecting proximity of vehicles, comprising: afirst vehicle at least partially coated with a near-IR reflectivecoating that increases a near-IR electromagnetic radiation detectiondistance by at least 15% as measured at a wavelength in a near-IR rangebetween the first vehicle and a second vehicle as compared to the firstvehicle coated with a color matched coating which absorbs more of thenear-IR radiation, wherein the color matched coating has a ΔE colormatched value of 1.5 or less when compared to the near-IR reflectivecoating, as measured using an integrating sphere with D65 Illumination,10° observer with specular component included.

Clause 29: The system of clause 28, wherein the near-IR reflectivecoating is substantially free of carbon black.

Clause 30: The system of clause 28 or 29, wherein the near-IR reflectivecoating covers at least 10 percent of an exterior surface area of thefirst vehicle.

Clause 31: The system of any of clauses 28-30, wherein the secondvehicle comprises an electromagnetic radiation source and anelectromagnetic radiation detector.

Clause 32: The system of any of clauses 28-31, wherein the near-IRreflective coating comprises at least one visibly-absorbing near-IRtransparent pigment and/or dye.

Clause 33: The system of any of clauses 28-32, wherein the near-IRreflective coating comprises at least a first coating layer and a secondcoating layer, wherein the first coating layer comprises at least onevisibly-absorbing near-IR transparent pigment and/or dye and the secondcoating layer comprises the at least one near-IR reflective pigment.

Clause 34: The system of any of clauses 28-33, wherein the near-IRreflective coating comprises a second coating layer positioned beneath afirst coating layer comprising at least one visibly-absorbing near-IRtransparent pigment and/or dye, wherein a second coating layercomprises: a film-forming resin; a plurality of near-IR transparentpigments and/or dyes dispersed in the film-forming resin, the pluralityof near-IR transparent pigments and/or dyes comprising a first perylenepigment and a second perylene pigment different from the first perylenepigment; and a near-IR reflective pigment dispersed in the film-formingresin, the near-IR reflective pigment different from the first perylenepigment and the second perylene pigment, wherein the second coatinglayer exhibits an off-white or grey color, and wherein the secondcoating layer is substantially free of carbon black.

Clause 35: The system of any of clauses 28-34, wherein the near-IRreflective coating comprises a second coating layer positioned beneath afirst coating layer comprising at least one visibly-absorbing near-IRtransparent pigment and/or dye, wherein a second coating layercomprises: a film-forming resin; a plurality of colorants dispersed inthe film-forming resin, the plurality of colorants comprising a near-IRtransparent pigment or dye, wherein the near-IR transparent pigment ordye comprises a first near-IR transparent pigment or dye and a secondnear-IR transparent pigment or dye different from the first near-IRtransparent pigment or dye; and a near-IR reflective pigment dispersedin the film-forming resin, the near-IR reflective pigment different fromthe first near-IR transparent pigment or dye and the second near-IRtransparent pigment or dye, wherein the second coating layer exhibits anoff-white or grey color, and wherein the second coating layer issubstantially free of carbon black.

Clause 36: The system of any of clauses 28-35, wherein the near-IRreflective coating has a reflectance of at least 20% for electromagneticradiation having a wavelength in a near-IR range.

Clause 37: The system of any of clauses 28-36, wherein the secondvehicle is an autonomously operated vehicle.

Clause 38: The system of any of clauses 28-37, wherein the near-IRreflective coating has a reflectance of at least 70% for electromagneticradiation having a wavelength in the near-IR range.

Clause 39: The system of any of clauses 28-38, wherein the near-IRreflective coating reflects electromagnetic radiation having at leastone wavelength in the range of 700 nm-2500 nm.

Clause 40: The system of any of clauses 28-39, wherein the near-IRreflective coating reflects electromagnetic radiation having at leastone wavelength in the range of 900 nm-1600 nm.

Clause 41: A system for detecting the proximity of a first vehicle to asecond vehicle, comprising: (a) a first vehicle at least partiallycoated with a near-IR reflective coating that increases a near-IRelectromagnetic radiation detection distance by at least 15% as measuredat a wavelength in a near-IR range as compared to a vehicle coated witha similar color matched coating which absorbs more of the near-IRradiation, wherein the similar color matched coating has a ΔE colormatched value of 1.5 or less when compared to the near-IR reflectivecoating, as measured using an integrating sphere with D65 Illumination,10° observer with specular component included; and (b) a second vehiclecomprising: (i) a near-IR electromagnetic radiation source that directsnear-IR electromagnetic radiation towards the first vehicle; (ii) anear-IR detector that detects near-IR electromagnetic radiationreflected from the first vehicle; and (iii) a computing device thatdetermines the detection distance between the first vehicle and secondvehicle based in part on the detected near-IR electromagnetic radiationreflected from the first vehicle.

Whereas particular embodiments of this invention have been describedabove for purposes of illustration, it will be evident to those skilledin the art that numerous variations of the details of the presentinvention may be made without departing from the invention as defined inthe appended claims.

The invention claimed is:
 1. A system for detecting proximity of anobject in a path of a vehicle, comprising: an object in the path of avehicle, wherein the object is at least partially coated with a near-IRreflective coating that increases a near-IR electromagnetic radiationdetection distance by at least 15% as measured at a wavelength in anear-IR range between the object and the vehicle as compared to theobject coated with a color matched coating which absorbs more of thenear-IR radiation, wherein the color matched coating has a ΔE colormatched value of 1.5 or less when compared to the near-IR reflectivecoating, as measured using an integrating sphere with D65 Illumination,10° observer with specular component included.
 2. The system of claim 1,wherein the vehicle comprises a vehicle onto which a near-IR radiationsource and/or a near-IR radiation detector is mounted.
 3. The system ofclaim 1, wherein the object comprises at least a portion of a road, roadtraffic safety product, signage, building, structure, or obstaclelocated in a path of a moving vehicle.
 4. The system of claim 1, whereinthe object comprises a second vehicle.
 5. The system of claim 1, whereinthe object comprises clothing worn by an individual in the path of thevehicle.
 6. The system of claim 1, wherein the near-IR reflectivecoating comprises at least one visibly-absorbing near-IR transparentpigment and/or dye.
 7. The system of claim 1, wherein the near-IRreflective coating comprises a first coating layer and a second coatinglayer, wherein the first coating layer comprises at least onevisibly-absorbing near-IR transparent pigment and/or dye and the secondcoating layer comprises at least one near-IR reflective pigment, whereinthe second coating layer underlies at least a portion of the firstcoating layer.
 8. The system of claim 7, wherein the second coatinglayer comprises: a film-forming resin; a plurality of near-IRtransparent pigments and/or dyes dispersed in the film-forming resin,the plurality of near-IR transparent pigments and/or dyes comprising afirst perylene pigment and a second perylene pigment different from thefirst perylene pigment; and a near-IR reflective pigment dispersed inthe film-forming resin, the near-IR reflective pigment different fromthe first perylene pigment and the second perylene pigment, wherein thesecond coating layer exhibits an off-white or grey color, and whereinthe second coating layer is substantially free of carbon black.
 9. Thesystem of claim 7, wherein the second coating layer comprises at leastone near-IR fluorescent pigment and/or dye.
 10. The system of claim 1,wherein the near-IR reflective coating covers at least 10% of anexterior surface area of the object.
 11. A method for increasing adetection distance of a surface of an object illuminated by near-IRelectromagnetic radiation, comprising: emitting electromagneticradiation having a wavelength of from 700 nm to 2500 nm from a radiationsource; detecting, using a radiation detector, at least a portion of theemitted electromagnetic radiation, wherein the detected at least aportion of the emitted electromagnetic radiation comprises radiationreflected from an object at least partially coated with a near-IRreflective coating that increases a near-IR electromagnetic radiationdetection distance by at least 15% as measured at a wavelength in anear-IR range as compared to the same object coated with a color matchedcoating which absorbs more of the same near-IR radiation, wherein thecolor matched coating has a ΔE color matched value of 1.5 or less whencompared to the near-IR reflective coating, as measured using anintegrating sphere with D65 Illumination, 10° observer with specularcomponent included.
 12. The method of claim 11, further comprising:determining a distance between the object and the radiation source basedon detecting the at least a portion of the emitted electromagneticradiation.
 13. The method of claim 11, wherein the radiation sourceand/or the radiation detector are mounted on a vehicle.
 14. The methodof claim 13, wherein the vehicle comprises an autonomous vehicle. 15.The method of method 11, wherein the emitted electromagnetic radiationhas a wavelength of from 900 nm to 1600 nm.
 16. The method of method 11,wherein the emitted electromagnetic radiation has a wavelength of 905 nmand/or 1550 nm.
 17. The method of method 11, wherein the near-IRreflective coating reflects at least 20% of the incident electromagneticradiation emitted from radiation source at the wavelength.
 18. Themethod of claim 11, wherein the electromagnetic radiation is emittedfrom the radiation source in the direction of the object, wherein theobject comprises a road, road traffic safety product, signage, building,structure, vehicle, clothing worn by an individual in the path of avehicle, and/or an obstacle located in a path of a vehicle.
 19. Themethod of claim 11, wherein the radiation source and/or the radiationdetector are components of a light imaging, detection and ranging(LIDAR) system.
 20. The method of claim 11, wherein the near-IRreflective coating comprises at least one visibly-absorbing near-IRtransparent pigment and/or dye.